Cobalt-based electrocatalysts take advantage of potentially harmonizable microstructure and flexible coupling effects compared to commercial noble metal-based catalytic materials.However,conventional water electrolysi...Cobalt-based electrocatalysts take advantage of potentially harmonizable microstructure and flexible coupling effects compared to commercial noble metal-based catalytic materials.However,conventional water electrolysis systems based on cobalt-based monofunctional hydrogen evolution reaction(HER)or oxygen evolution reaction(OER)catalysts have certain shortcomings in terms of resource utilization and universality.In contrast,cobalt-based bifunctional catalysts(CBCs)have attracted much attention in recent years for overall water splitting systems because of their practicality and reduced preparation cost of electrolyzer.This review aims to address the latest development in CBCs for total hydrolysis.The main modification strategies of CBCs are systematically classified in water electrolysis to provide an overview of how to regulate their morphology and electronic configuration.Then,the catalytic performance of CBCs in total-hydrolysis is summarized according to the types of cobalt-based phosphides,sulfides and oxides,and the mechanism of strengthened electrocatalytic ability is emphasized through combining experiments and theoretical calculations.Future efforts are finally suggested to focus on exploring the dynamic conversion of reaction intermediates and building near-industrial CBCs,designing advanced CBC materials through micro-modulation,and addressing commercial applications.展开更多
Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catal...Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.展开更多
Here,a styrene-based polymer monolithic column poly(VBS-co-TAT-co-AHM)with reversed-phase/hydrophilic interaction liquid chromatography(RPLC/HILIC)bifunctional separation mode was success-fully prepared for capillary ...Here,a styrene-based polymer monolithic column poly(VBS-co-TAT-co-AHM)with reversed-phase/hydrophilic interaction liquid chromatography(RPLC/HILIC)bifunctional separation mode was success-fully prepared for capillary electrochromatography by the in situ polymerization of sodium p-styrene sulfonate(VBS)with cross-linkers 3-(acryloyloxy)-2-hydroxypropyl methacrylate(AHM)and 1,3,5-triacryloylhexahydro-1,3,5-triazine(TAT).The preparation conditions of the monolith were optimized.The morphology and formation of the poly(VBS-co-TAT-co-AHM)monolith were confirmed by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The separation perfor-mances of the monolith were evaluated systematically.It should be noted that the incorporation of VBS functional monomer can provideπ-πinteractions,hydrophilic interactions,and ion-exchange in-teractions.Hence,the prepared poly(VBS-co-TAT-co-AHM)monolith can achieve efficient separation of thiourea compounds,benzene series,phenol compounds,aniline compounds and sulfonamides in RPLC or HILIC separation mode.The largest theoretical plate number for N,N0-dimethylthiourea reached 1.7×10^(5)plates/m.In addition,the poly(VBS-co-TAT-co-AHM)monolithic column showed excellent reproducibility and stability.This novel monolithic column has great application value and potential in capillary electrochromatography(CEC).展开更多
Water-splitting reactions such as the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)typically require expensive noble metal-based electrocatalysts.This has motivated researchers to develop nove...Water-splitting reactions such as the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)typically require expensive noble metal-based electrocatalysts.This has motivated researchers to develop novel,cost-effective electrocatalytic systems.In this study,a new multicomponent nanocomposite was assembled by combining functionalized multiwalled carbon nanotubes,a Cu-based metal–organic framework(MOF)(HKUST-1 or HK),and a sulfidized NiMn-layered double hydroxide(NiMn-S).The resulting nanocomposite,abbreviated as MW/HK/NiMn-S,features a unique architecture,high porosity,numerous electroactive Cu/Ni/Mn sites,fast charge transfer,excellent structural stability,and conductivity.At a current density of 10 mA cm-2,this dual-function electrocatalyst shows remarkable performance,with ultralow overpotential values of 163 mV(OER)or 73 mV(HER),as well as low Tafel slopes(57 and 75 mV dec-1,respectively).Additionally,its high turnover frequency values(4.43 s-1 for OER;3.96 s-1 for HER)are significantly superior to those of standard noble metal-based Pt/C and IrO2 systems.The synergistic effect of the nanocomposite's different components is responsible for its enhanced electrocatalytic performance.A density functional theory study revealed that the multi-interface and multicomponent heterostructure contribute to increased electrical conductivity and decreased energy barrier,resulting in superior electrocatalytic HER/OER activity.This study presents a novel vision for designing advanced electrocatalysts with superior performance in water splitting.Various composites have been utilized in water-splitting applications.This study investigates the use of the MW/HK/NiMn-S electrocatalyst for water splitting for the first time to indicate the synergistic effect between carbon-based materials along with layered double hydroxide compounds and porous compounds of MOF.The unique features of each component in this composite can be an interesting topic in the field of water splitting.展开更多
Highly active bifunctional oxygen electrocatalysts accelerate the development of high-performance Zn-air battery,but suffer from the mismatched activities of oxygen evolution reaction(OER)and oxygen reduced reaction(O...Highly active bifunctional oxygen electrocatalysts accelerate the development of high-performance Zn-air battery,but suffer from the mismatched activities of oxygen evolution reaction(OER)and oxygen reduced reaction(ORR).Herein,highly integrated bifunctional oxygen electrocatalysts,cobalt-tin alloys coated by nitrogen doped carbon(CoSn@NC)are prepared by MOFs-derived method.In this hybrid catalyst,the binary CoSn nanoalloys mainly contribute to highly active OER process while the Co(or Sn)-N-C serves as ORR active sites.Rational interaction between CoSn and NC donates more rapid reaction kinetics than Pt/C(ORR)and IrO_(2)(OER).Such CoSn@NC holds a promise as air-cathode electrocatalyst in Zn-air battery,superior to Pt/C+IrO_(2)catalyst.First-principles calculations predict that CoSn alloys can upgrade charge redistribution on NC and promote the transfer to reactants,thus optimizing the adsorption strength of oxygen-containing intermediates to boost the overall reactivity.The tuning of oxygenate adsorption by interactions between alloy and heteroatom-doped carbon can guide the design of bifunctional oxygen electrocatalysts.展开更多
Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits ina...Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.展开更多
Improving catalytic activity and durabilty through the structural and compositional development of bifunctional electrocatalysts with low cost,high activity and stability is a challenging issue in electrochemical wate...Improving catalytic activity and durabilty through the structural and compositional development of bifunctional electrocatalysts with low cost,high activity and stability is a challenging issue in electrochemical water splitting.Herein,we report the fabrication of heterostructured P-CoMoO_(4)@NiCoP on a Ni foam substrate through interface engineering,by adjusting its composition and architecture.Benefitting from the tailored electronic structure and exposed active sites,the heterostructured P-CoMoO_(4)@NiCoP/NF arrays can be coordinated to boost the overall water splitting.In addition,the superhydrophilic and superaerophobic properties of P-CoMoO_(4)@NiCoP/NF make it conducive to water dissociation and bubble separation in the electrocatalytic process.The heterostructured PCoMoO_(4)@NiCoP/NF exhibits excellent bifunctional electrocatalysis activity with a low overpotential of 66 mV at 10 mA cm^(-2) for HER and 252 mV at 100 mA cm^(-2) for OER.Only 1.62 V potential is required to deliver 20 mA cm^(-2) in a two-electrode electrolysis system,providing a decent overall water splitting performance.The rational construction of the heterostructure makes it possible to regulate the electronic structures and active sites of the electrocatalysts to promote their catalytic activity.展开更多
The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexame...The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.展开更多
Transition-metal phosphides(TMPs)with high catalytic activity are widely used in the design of electrodes for water splitting.However,a major challenge is how to achieve the trade-off between activity and stability of...Transition-metal phosphides(TMPs)with high catalytic activity are widely used in the design of electrodes for water splitting.However,a major challenge is how to achieve the trade-off between activity and stability of TMPs.Herein,a novel method for synthesizing CoP nanoparticles encapsu-lated in a rich-defect carbon shell(CoP/DCS)is developed through the self-assembly of modified polycyclic aromatic molecules.The graft and removal of high-activity C-N bonds of aromatic molecules render the controllable design of crystallite defects of carbon shell.The density functional theory calculation indicates that the carbon defects with unpaired electrons could effectively tailor the band structure of CoP.Benefiting from the improved activity and corrosion resistance,the CoP/DCS delivers outstanding difunctional hydrogen evolution reaction(88 mV)and oxygen evolution reaction(251 mV)performances at 10 mA cm^(−2)current density.Furthermore,the coupled water electrolyzer with CoP/DCS as both the cathode and anode presents ultralow cell voltages of 1.49 V to achieve 10 mA cm^(−2)with long-time stability.This strategy to improve TMPs electrocatalyst with rich-DCS and heterogeneous structure will inspire the design of other transition metal compound electrocatalysts for water splitting.展开更多
The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient s...The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB.In this study,the bimetallic ZIFs-containing electrospun(ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process,which was expected to be a bifunctional electrocatalyst for ZABs.Owing to the formed dual single-atomic sites of Co-N_(4) and Zn-N_(4),the obtained ES-Co/ZnCNZIFexhibited the preferable performance toward oxygen reduction reaction(ORR) with E1/2of 0.857 V and JLof 5.52 mA cm^(-2),which were more than Pt/C.Meanwhile,it exhibited a marked oxygen evolution reaction(OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles.Furthermore,the ZAB based on the ES-Co/Zn-CNZIFcarbon nanofibers membranes delivered peak power density of 215 mW cm^(-2),specific capacity of 802.6 mA h g^(-1),and exceptional cycling stability,far larger than Pt/C+RuO_(2)-based ZABs.A solid-state ZAB based on ES-Co/Zn-CNZIFshowed better flexibility and stability with different bending angles.展开更多
An in situ coupling strategy to prepare Co_9S_8/S and N dual?doped graphene composite(Co_9S_8/NSG) has been proposed. The key point of this strategy is the function?oriented design of organic compounds. Herein, cobalt...An in situ coupling strategy to prepare Co_9S_8/S and N dual?doped graphene composite(Co_9S_8/NSG) has been proposed. The key point of this strategy is the function?oriented design of organic compounds. Herein, cobalt porphyrin derivatives with sulfo groups are employed as not only the coupling agents to form and anchor Co_9S_8 on the graphene in situ, but also the heteroatom?doped agent to generate S and N dual?doped graphene. The tight coupling of multiple active sites endows the composite materials with fast electrochemical kinetics and excellent stability for both oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). The obtained electrocatalyst exhibits better activity parameter(ΔE = 0.82 V) and smaller Tafel slope(47.7 mV dec^(-1) for ORR and 69.2 mV dec^(-1) for OER) than commercially available Pt/C and RuO_2. Most importantly, as electrocatalyst for rechargeable Zn–air battery, Co_9S_8/NSG displays low charge–discharge voltage gap and outstanding long?term cycle stability over 138 h compared to Pt/C–RuO_2. To further broaden its application scope, a homemade all?solid?state Zn–air battery is also prepared, which displays good charge–discharge performance and cycle performance. The function?oriented design of N_4?metallomacrocycle derivatives might open new avenues to strategic construction of high?performance and long?life multifunctional electrocatalysts for wider electro?chemical energy applications.展开更多
The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electro...The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electrolysers, fuel cells, and metal–air batteries emerge in response to the need for developing sustainable energy carriers, in which the oxygen evolution reaction and the oxygen reduction reaction play key roles. However, both reactions suffer from sluggish kinetics that restricts the reactivity. Therefore, it is vital to probe into the structure of the catalysts to exploit high-performance bifunctional oxygen electrocatalysts. Spinel-type catalysts are a class of materials with advantages of versatility, low toxicity, low expense, high abundance, flexible ion arrangement, and multivalence structure. In this review, we afford a basic overview of spinel-type materials and then introduce the relevant theoretical principles for electrocatalytic activity, following that we shed light on the structure–property relationship strategies for spinel-type catalysts including electronic structure, microstructure, phase and composition regulation,and coupling with electrically conductive supports. We elaborate the relationship between structure and property, in order to provide some insights into the design of spinel-type bifunctional oxygen electrocatalysts.展开更多
Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance...Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially unviable.Since good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very desirable.Alternative catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable production.To overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen catalysts.The tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good durability.Thus,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen catalysts.In the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been discussed.The selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green process.The synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxygen catalysts for commercial energy applications.Recent advances and the importance of biomass-based bifunctional oxygen catalysts in metal-air batteries and fuel cells has been highlighted.The material design,perspectives and future directions in this field are also provided.展开更多
The design and development of low-cost,efficient,and stable bifunctional electrocatalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desirable for rechargeable metal-air batteries.In t...The design and development of low-cost,efficient,and stable bifunctional electrocatalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desirable for rechargeable metal-air batteries.In this work,N-doped porous hollow carbon spheres encapsulated with ultrafine Fe/Fe3O4 nanoparticles(FeOx@N-PHCS)were fabricated by impregnation and subsequent pyrolysis,using melamine-formaldehyde resin spheres as self-sacrifice templates and polydopamine as N and C sources.The sufficient adsorption of Fe3+on the polydopamine endowed the formation of Fe-Nx species upon high-temperature carbonization.The prepared FeOx@N-PHCS has advanced features of large specific surface area,porous hollow structure,high content of N dopants,sufficient Fe-Nx species and ultrafine FeOx nanoparticles.These features endow FeOx@N-PHCS with enhanced mass transfer and considerable active sites,leading to high activity and stability in catalyzing ORR and OER in alkaline electrolyte.Furthermore,the rechargeable Zn-air battery with FeOx@N-PHCS as air cathode catalyst exhibits a large peak power density,narrow charge-discharge potential gap and robust cycling stability,demonstrating the potential of the fabricated FeOx@N-PHCS as a promising electrode material for metal-air batteries.This new finding may open an avenue for rational design of bifunctional catalysts by integrating different active components within all-in-one catalyst for different electrochemical reactions.展开更多
Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactiv...Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.展开更多
The inefficiency of water splitting is mainly due to the sluggish anodic water oxidation reaction. Replacing water oxidation with thermodynamically more favorable selective methanol oxidation reaction and developing r...The inefficiency of water splitting is mainly due to the sluggish anodic water oxidation reaction. Replacing water oxidation with thermodynamically more favorable selective methanol oxidation reaction and developing robust bifunctional electrocatalysts are of great significance. Herein, a hierarchical heteronanostructure with Ni–Co layered double hydroxide(LDH) ultrathin nanosheets coated on cobalt phosphide nanosheets arrays(CoxP@NiCo-LDH) are fabricated and used for co-electrolysis of methanol/water to co-produce value-added formate and hydrogen with saving energy. Benefiting from the fast charge transfer introduced by phosphide nanoarrays, the synergy in nanosheets catalysts with hetero-interface,CoxP@NiCo-LDH/Ni foam(NF) exhibits superior electrocatalytic performance(10 mA cm-2@ 1.24 V and-0.10 V for methanol selective oxidation and hydrogen evolution reaction, respectively). Furthermore,CoxP@NiCo-LDH/NF-based symmetric two-electrode electrolyzer drives a current density of 10 m A cm-2 with a low cell voltage of only 1.43 V and the Faradaic efficiency towards the generation of formate and H2 are close to 100% in the tested range of current density(from 40 to 200 m A cm-2). This work highlights the positive effect of hetero-interaction in the design of more efficient eletrocatalysts and might guide the way towards facile upgrading of alcohols and energy-saving electrolytic H2 co-generation.展开更多
Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped Co...Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.展开更多
Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hier...Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hierarchical sulfur and nitrogen co-doped carbon nanocages(hSNCNC) as a promising bifunctional oxygen electrocatalyst by an in-situ MgO template method with pyridine and thiophene as the mixed precursor. The as-prepared h SNCNC exhibits a positive half-wave potential of 0.792 V(vs. reversible hydrogen electrode, RHE) for ORR, and a low operating potential of 1.640 V at a 10 mA cm-2 current density for OER. The reversible oxygen electrode index is 0.847 V, far superior to commercial Pt/C and IrO2,which reaches the top level of the reported bifunctional catalysts. Consequently, the hSNCNC as air cathodes in an assembled Zn-air battery features low charge/discharge overpotential and long lifetime. The remarkable properties arises from the introduced multiple heteroatom dopants and stable 3D hierarchical structure with multi-scale pores, which provides the abundant uniform high-active S and N species and efficient charge transfer as well as mass transportation. These results demonstrate the potential strategy in developing suitable carbon-based bi-/multi-functional catalysts to enable the next generation of the rechargeable metal-air batteries.展开更多
Rational design of efficient bifunctional electrocatalysts is highly imperative but still a challenge for overall water splitting.Herein,we construct novel freestanding Mo-doped NiCoP nanosheet arrays by the hydrother...Rational design of efficient bifunctional electrocatalysts is highly imperative but still a challenge for overall water splitting.Herein,we construct novel freestanding Mo-doped NiCoP nanosheet arrays by the hydrothermal and phosphation processes,serving as bifunctional electrocatalysts for overall water splitting.Notably,Mo doping could effectively modulate the electronic structure of NiCoP,leading to the increased electroactive site and improved intrinsic activity of each site.Furthermore,an electrochemical activation strategy is proposed to form Mo-doped(Ni,Co)OOH to fully boost the electrocatalytic activities for oxygen evolution reaction.Benefiting from the unique freestanding structure and Mo doping,Mo-doped NiCoP and(Ni,Co)OOH show the remarkable electrochemical performances,which are competitive among current researches.In addition,an overall water splitting device assembled by both electrodes only requires a cell voltage of 1.61 V to reach a current density of 10 mA cm?2.Therefore,this work opens up new avenues for designing nonprecious bifunctional electrocatalysts by Mo doping and in situ electrochemical activation.展开更多
The rational design and development of cost-effective,high-performance,and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts are essential for rechargeable zinc-air b...The rational design and development of cost-effective,high-performance,and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts are essential for rechargeable zinc-air batteries.Herein,a novel FeCo composite composed of alloy nanoparticles embedded in an N,S dual-doped carbon matrix(FeCo/NSC)was prepared via one-step carbonization of amphiphilic dodecanethiol-metal salts wrapped in carbon nitride(C_(3)N_(4)).The compact combination of dual metalalloys and dual-doped carbon endowed the composite with the active sites for the ORR and OER,achieving efficient electrical transmission and highly efficient bifunctional catalytic performance.The obtained FeCo-1/NSC catalyst exhibited excellent electrocatalytic activity with a half-wave potential of 0.82 V(vs.RHE)for the ORR and a low overpotential of 0.325 V at 10 mA cm^(-2) for the OER.The liquid Zn-air battery with FeCo-1/NSC as an air electrode displayed excellent charge-discharge performance,high power density,and robust charge-discharge stability for 150 h compared to the 20%Pt/C+RuO_(2) counterpart.Furthermore,the FeCo-1/NSC-based flexible solid-state Zn-air battery exhibited a higher power density and good charge-discharge stability over 10 h of operation.Thus,a promising strategy for bifunctional electrocatalyst development as part of rechargeable and wearable Zn-air batteries was provided.展开更多
基金financially supported by the National Natural Science Foundation of China(51572166,52102070)the Program for Professor of Special Appointment at Shanghai Institutions of Higher Learning(GZ2020012)+4 种基金the Key Research Project of Zhejiang Laboratory(2021PE0AC02)the China Postdoctoral Science Foundation(2021M702073)BAJC R&D Fund Projects(BA23011)Australian Research Council Future Fellowships(FT230100436)the Shanghai Technical Service Center for Advanced Ceramics Structure Design and Precision Manufacturing(20DZ2294000)。
文摘Cobalt-based electrocatalysts take advantage of potentially harmonizable microstructure and flexible coupling effects compared to commercial noble metal-based catalytic materials.However,conventional water electrolysis systems based on cobalt-based monofunctional hydrogen evolution reaction(HER)or oxygen evolution reaction(OER)catalysts have certain shortcomings in terms of resource utilization and universality.In contrast,cobalt-based bifunctional catalysts(CBCs)have attracted much attention in recent years for overall water splitting systems because of their practicality and reduced preparation cost of electrolyzer.This review aims to address the latest development in CBCs for total hydrolysis.The main modification strategies of CBCs are systematically classified in water electrolysis to provide an overview of how to regulate their morphology and electronic configuration.Then,the catalytic performance of CBCs in total-hydrolysis is summarized according to the types of cobalt-based phosphides,sulfides and oxides,and the mechanism of strengthened electrocatalytic ability is emphasized through combining experiments and theoretical calculations.Future efforts are finally suggested to focus on exploring the dynamic conversion of reaction intermediates and building near-industrial CBCs,designing advanced CBC materials through micro-modulation,and addressing commercial applications.
基金the National Key Research and Development Program of China (No. 2020YFA0211004)Key Grant of Nation Science Funding of China (No. 22236005)+5 种基金Nation Science Funding of China (No. 22376141)Ministry of Education of China (No. PCSIRT_IRT_16R49)“111” Innovation and Talent Recruitment Base (D18020)Shanghai Government (No. 20ZR1440700)Shanghai Engineering Research Center of Green Energy Chemical Engineering (No. 18DZ2254200)Scientific and Technological Innovation Team for Green Catalysis and Energy Materialien Yunnan Institutions of Higher Learning, and Surface project of Yunnan Province science and technology Department (No. 20210 A070001-050).
文摘Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.
基金the National Natural Science Foundation of China(Grant Nos.:82273885,82073808 and 81872828).
文摘Here,a styrene-based polymer monolithic column poly(VBS-co-TAT-co-AHM)with reversed-phase/hydrophilic interaction liquid chromatography(RPLC/HILIC)bifunctional separation mode was success-fully prepared for capillary electrochromatography by the in situ polymerization of sodium p-styrene sulfonate(VBS)with cross-linkers 3-(acryloyloxy)-2-hydroxypropyl methacrylate(AHM)and 1,3,5-triacryloylhexahydro-1,3,5-triazine(TAT).The preparation conditions of the monolith were optimized.The morphology and formation of the poly(VBS-co-TAT-co-AHM)monolith were confirmed by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The separation perfor-mances of the monolith were evaluated systematically.It should be noted that the incorporation of VBS functional monomer can provideπ-πinteractions,hydrophilic interactions,and ion-exchange in-teractions.Hence,the prepared poly(VBS-co-TAT-co-AHM)monolith can achieve efficient separation of thiourea compounds,benzene series,phenol compounds,aniline compounds and sulfonamides in RPLC or HILIC separation mode.The largest theoretical plate number for N,N0-dimethylthiourea reached 1.7×10^(5)plates/m.In addition,the poly(VBS-co-TAT-co-AHM)monolithic column showed excellent reproducibility and stability.This novel monolithic column has great application value and potential in capillary electrochromatography(CEC).
基金Iran National Science Foundation(INSF)under project No.4025105the Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(Grant No.2022-K31)+1 种基金the Zhejiang Province Key Research and Development Project(2023 C01191)Alexander M.Kirillov acknowledges the Foundation for Science and Technology(LISBOA-01-0145-FEDER-029697,PTDC/QUIQIN/3898/2020,LA/P/0056/2020,UIDB/00100/2020).
文摘Water-splitting reactions such as the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)typically require expensive noble metal-based electrocatalysts.This has motivated researchers to develop novel,cost-effective electrocatalytic systems.In this study,a new multicomponent nanocomposite was assembled by combining functionalized multiwalled carbon nanotubes,a Cu-based metal–organic framework(MOF)(HKUST-1 or HK),and a sulfidized NiMn-layered double hydroxide(NiMn-S).The resulting nanocomposite,abbreviated as MW/HK/NiMn-S,features a unique architecture,high porosity,numerous electroactive Cu/Ni/Mn sites,fast charge transfer,excellent structural stability,and conductivity.At a current density of 10 mA cm-2,this dual-function electrocatalyst shows remarkable performance,with ultralow overpotential values of 163 mV(OER)or 73 mV(HER),as well as low Tafel slopes(57 and 75 mV dec-1,respectively).Additionally,its high turnover frequency values(4.43 s-1 for OER;3.96 s-1 for HER)are significantly superior to those of standard noble metal-based Pt/C and IrO2 systems.The synergistic effect of the nanocomposite's different components is responsible for its enhanced electrocatalytic performance.A density functional theory study revealed that the multi-interface and multicomponent heterostructure contribute to increased electrical conductivity and decreased energy barrier,resulting in superior electrocatalytic HER/OER activity.This study presents a novel vision for designing advanced electrocatalysts with superior performance in water splitting.Various composites have been utilized in water-splitting applications.This study investigates the use of the MW/HK/NiMn-S electrocatalyst for water splitting for the first time to indicate the synergistic effect between carbon-based materials along with layered double hydroxide compounds and porous compounds of MOF.The unique features of each component in this composite can be an interesting topic in the field of water splitting.
基金This work was financially supported by Shanghai Science and Technology Innovation Action Plan(Program No.20DZ1204400)the Key Research Program of Frontier Science,Chinese Academy of Sciences(Grant No.QYZDJSSW-JSC013).
文摘Highly active bifunctional oxygen electrocatalysts accelerate the development of high-performance Zn-air battery,but suffer from the mismatched activities of oxygen evolution reaction(OER)and oxygen reduced reaction(ORR).Herein,highly integrated bifunctional oxygen electrocatalysts,cobalt-tin alloys coated by nitrogen doped carbon(CoSn@NC)are prepared by MOFs-derived method.In this hybrid catalyst,the binary CoSn nanoalloys mainly contribute to highly active OER process while the Co(or Sn)-N-C serves as ORR active sites.Rational interaction between CoSn and NC donates more rapid reaction kinetics than Pt/C(ORR)and IrO_(2)(OER).Such CoSn@NC holds a promise as air-cathode electrocatalyst in Zn-air battery,superior to Pt/C+IrO_(2)catalyst.First-principles calculations predict that CoSn alloys can upgrade charge redistribution on NC and promote the transfer to reactants,thus optimizing the adsorption strength of oxygen-containing intermediates to boost the overall reactivity.The tuning of oxygenate adsorption by interactions between alloy and heteroatom-doped carbon can guide the design of bifunctional oxygen electrocatalysts.
基金financially supported by the National Natural Science Foundation of China(No.21975163)the Shenzhen Innovative Research Team Program(KQTD20190929173914967)the Senior Talent Research Start-up Fund of Shenzhen University(000265)。
文摘Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.
基金The authors acknowledge the National Natural Science Foundation of China(NSFC 91834301,21808046 and 21908037)Anhui Provincial Science and Technology Department Foundation(201903a05020021 and 202003a05020046)for funding support.
文摘Improving catalytic activity and durabilty through the structural and compositional development of bifunctional electrocatalysts with low cost,high activity and stability is a challenging issue in electrochemical water splitting.Herein,we report the fabrication of heterostructured P-CoMoO_(4)@NiCoP on a Ni foam substrate through interface engineering,by adjusting its composition and architecture.Benefitting from the tailored electronic structure and exposed active sites,the heterostructured P-CoMoO_(4)@NiCoP/NF arrays can be coordinated to boost the overall water splitting.In addition,the superhydrophilic and superaerophobic properties of P-CoMoO_(4)@NiCoP/NF make it conducive to water dissociation and bubble separation in the electrocatalytic process.The heterostructured PCoMoO_(4)@NiCoP/NF exhibits excellent bifunctional electrocatalysis activity with a low overpotential of 66 mV at 10 mA cm^(-2) for HER and 252 mV at 100 mA cm^(-2) for OER.Only 1.62 V potential is required to deliver 20 mA cm^(-2) in a two-electrode electrolysis system,providing a decent overall water splitting performance.The rational construction of the heterostructure makes it possible to regulate the electronic structures and active sites of the electrocatalysts to promote their catalytic activity.
基金funded by the National Key Research and Development Project,Intergovernmental International Science and Technology Innovation Cooperation Key Project(No.2018YFE0108800)National Natural Science Foundation of China(No.22278115)Heilongjiang Province Natural Science Foundation(No.YQ2021B010).
文摘The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.
基金Youth Innovation Promotion Association of the Chinese Academy of Sciences,Grant/Award Number:2021174National Natural Science Foundation of China,Grant/Award Number:51902326Natural Science Foundation of Shanxi Province,Grant/Award Numbers:201901D211588,20210302124421。
文摘Transition-metal phosphides(TMPs)with high catalytic activity are widely used in the design of electrodes for water splitting.However,a major challenge is how to achieve the trade-off between activity and stability of TMPs.Herein,a novel method for synthesizing CoP nanoparticles encapsu-lated in a rich-defect carbon shell(CoP/DCS)is developed through the self-assembly of modified polycyclic aromatic molecules.The graft and removal of high-activity C-N bonds of aromatic molecules render the controllable design of crystallite defects of carbon shell.The density functional theory calculation indicates that the carbon defects with unpaired electrons could effectively tailor the band structure of CoP.Benefiting from the improved activity and corrosion resistance,the CoP/DCS delivers outstanding difunctional hydrogen evolution reaction(88 mV)and oxygen evolution reaction(251 mV)performances at 10 mA cm^(−2)current density.Furthermore,the coupled water electrolyzer with CoP/DCS as both the cathode and anode presents ultralow cell voltages of 1.49 V to achieve 10 mA cm^(−2)with long-time stability.This strategy to improve TMPs electrocatalyst with rich-DCS and heterogeneous structure will inspire the design of other transition metal compound electrocatalysts for water splitting.
基金supported by the Beijing Natural Science Foundation (2222004)。
文摘The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB.In this study,the bimetallic ZIFs-containing electrospun(ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process,which was expected to be a bifunctional electrocatalyst for ZABs.Owing to the formed dual single-atomic sites of Co-N_(4) and Zn-N_(4),the obtained ES-Co/ZnCNZIFexhibited the preferable performance toward oxygen reduction reaction(ORR) with E1/2of 0.857 V and JLof 5.52 mA cm^(-2),which were more than Pt/C.Meanwhile,it exhibited a marked oxygen evolution reaction(OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles.Furthermore,the ZAB based on the ES-Co/Zn-CNZIFcarbon nanofibers membranes delivered peak power density of 215 mW cm^(-2),specific capacity of 802.6 mA h g^(-1),and exceptional cycling stability,far larger than Pt/C+RuO_(2)-based ZABs.A solid-state ZAB based on ES-Co/Zn-CNZIFshowed better flexibility and stability with different bending angles.
基金supported by the National Natural Science Foundation of China (Grant No. 21404014)the Science & Technology Department of Jilin Province (No. 20170101177JC)
文摘An in situ coupling strategy to prepare Co_9S_8/S and N dual?doped graphene composite(Co_9S_8/NSG) has been proposed. The key point of this strategy is the function?oriented design of organic compounds. Herein, cobalt porphyrin derivatives with sulfo groups are employed as not only the coupling agents to form and anchor Co_9S_8 on the graphene in situ, but also the heteroatom?doped agent to generate S and N dual?doped graphene. The tight coupling of multiple active sites endows the composite materials with fast electrochemical kinetics and excellent stability for both oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). The obtained electrocatalyst exhibits better activity parameter(ΔE = 0.82 V) and smaller Tafel slope(47.7 mV dec^(-1) for ORR and 69.2 mV dec^(-1) for OER) than commercially available Pt/C and RuO_2. Most importantly, as electrocatalyst for rechargeable Zn–air battery, Co_9S_8/NSG displays low charge–discharge voltage gap and outstanding long?term cycle stability over 138 h compared to Pt/C–RuO_2. To further broaden its application scope, a homemade all?solid?state Zn–air battery is also prepared, which displays good charge–discharge performance and cycle performance. The function?oriented design of N_4?metallomacrocycle derivatives might open new avenues to strategic construction of high?performance and long?life multifunctional electrocatalysts for wider electro?chemical energy applications.
基金supported by the Natural Scientific Foundation of China (21825501)National Key Research and Development Program (2016YFA0202500 and 2016YFA0200102)+1 种基金Australian Research Council (DP160103107, FT170100224)Tsinghua University Initiative Scientific Research Program。
文摘The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electrolysers, fuel cells, and metal–air batteries emerge in response to the need for developing sustainable energy carriers, in which the oxygen evolution reaction and the oxygen reduction reaction play key roles. However, both reactions suffer from sluggish kinetics that restricts the reactivity. Therefore, it is vital to probe into the structure of the catalysts to exploit high-performance bifunctional oxygen electrocatalysts. Spinel-type catalysts are a class of materials with advantages of versatility, low toxicity, low expense, high abundance, flexible ion arrangement, and multivalence structure. In this review, we afford a basic overview of spinel-type materials and then introduce the relevant theoretical principles for electrocatalytic activity, following that we shed light on the structure–property relationship strategies for spinel-type catalysts including electronic structure, microstructure, phase and composition regulation,and coupling with electrically conductive supports. We elaborate the relationship between structure and property, in order to provide some insights into the design of spinel-type bifunctional oxygen electrocatalysts.
基金supported in part by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2019H1D3A2A02102086)the Hydrogen Energy Innovation Technology Development Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, & Future Planning (2019M3E6A1063677)。
文摘Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially unviable.Since good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very desirable.Alternative catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable production.To overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen catalysts.The tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good durability.Thus,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen catalysts.In the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been discussed.The selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green process.The synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxygen catalysts for commercial energy applications.Recent advances and the importance of biomass-based bifunctional oxygen catalysts in metal-air batteries and fuel cells has been highlighted.The material design,perspectives and future directions in this field are also provided.
基金supported by the National Natural Science Foundation of China(21421001,21573115,21875118)Tianjin Science and Technology Commission(18JCTPJC55900)+1 种基金the Natural Science Foundation of Tianjin(17JCYBJC17100,19JCZDJC37700)the 111 Project(B12015).
文摘The design and development of low-cost,efficient,and stable bifunctional electrocatalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desirable for rechargeable metal-air batteries.In this work,N-doped porous hollow carbon spheres encapsulated with ultrafine Fe/Fe3O4 nanoparticles(FeOx@N-PHCS)were fabricated by impregnation and subsequent pyrolysis,using melamine-formaldehyde resin spheres as self-sacrifice templates and polydopamine as N and C sources.The sufficient adsorption of Fe3+on the polydopamine endowed the formation of Fe-Nx species upon high-temperature carbonization.The prepared FeOx@N-PHCS has advanced features of large specific surface area,porous hollow structure,high content of N dopants,sufficient Fe-Nx species and ultrafine FeOx nanoparticles.These features endow FeOx@N-PHCS with enhanced mass transfer and considerable active sites,leading to high activity and stability in catalyzing ORR and OER in alkaline electrolyte.Furthermore,the rechargeable Zn-air battery with FeOx@N-PHCS as air cathode catalyst exhibits a large peak power density,narrow charge-discharge potential gap and robust cycling stability,demonstrating the potential of the fabricated FeOx@N-PHCS as a promising electrode material for metal-air batteries.This new finding may open an avenue for rational design of bifunctional catalysts by integrating different active components within all-in-one catalyst for different electrochemical reactions.
基金supported by the National Key Research and Development Program(2016YFA0202500)National Natural Science Foundation of China(21776019,21808124,51972121)+1 种基金Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2017TQ04C419)Beijing Natural Science Foundation(L182021)。
文摘Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.
基金financially supported by the National Natural Science Foundation of China(Nos.21975163 and 21905181)。
文摘The inefficiency of water splitting is mainly due to the sluggish anodic water oxidation reaction. Replacing water oxidation with thermodynamically more favorable selective methanol oxidation reaction and developing robust bifunctional electrocatalysts are of great significance. Herein, a hierarchical heteronanostructure with Ni–Co layered double hydroxide(LDH) ultrathin nanosheets coated on cobalt phosphide nanosheets arrays(CoxP@NiCo-LDH) are fabricated and used for co-electrolysis of methanol/water to co-produce value-added formate and hydrogen with saving energy. Benefiting from the fast charge transfer introduced by phosphide nanoarrays, the synergy in nanosheets catalysts with hetero-interface,CoxP@NiCo-LDH/Ni foam(NF) exhibits superior electrocatalytic performance(10 mA cm-2@ 1.24 V and-0.10 V for methanol selective oxidation and hydrogen evolution reaction, respectively). Furthermore,CoxP@NiCo-LDH/NF-based symmetric two-electrode electrolyzer drives a current density of 10 m A cm-2 with a low cell voltage of only 1.43 V and the Faradaic efficiency towards the generation of formate and H2 are close to 100% in the tested range of current density(from 40 to 200 m A cm-2). This work highlights the positive effect of hetero-interaction in the design of more efficient eletrocatalysts and might guide the way towards facile upgrading of alcohols and energy-saving electrolytic H2 co-generation.
基金financially supported by the National Natural Science Foundation of China(21776314)Major Program of Shandong Province Natural Science Foundation(ZR2018ZC0639)+2 种基金Shandong Provincial Natural Science Foundation(ZR2017MB059)the Fundamental Research Funds for the Central Universities(18CX05016A)Postgraduate Innovation Project of China University of Petroleum(YCX2018034)
文摘Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.
基金financial support from the National Natural Science Foundation of China (21773111, 21473089, 21573107 and 51571110)the National Key Research and Development Program of China (2017YFA0206503, 2018YFA0209103)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions, Fundamental Research Funds for the Central Universitiesthe program B for outstanding PhD candidate of Nanjing University (201702B049)
文摘Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hierarchical sulfur and nitrogen co-doped carbon nanocages(hSNCNC) as a promising bifunctional oxygen electrocatalyst by an in-situ MgO template method with pyridine and thiophene as the mixed precursor. The as-prepared h SNCNC exhibits a positive half-wave potential of 0.792 V(vs. reversible hydrogen electrode, RHE) for ORR, and a low operating potential of 1.640 V at a 10 mA cm-2 current density for OER. The reversible oxygen electrode index is 0.847 V, far superior to commercial Pt/C and IrO2,which reaches the top level of the reported bifunctional catalysts. Consequently, the hSNCNC as air cathodes in an assembled Zn-air battery features low charge/discharge overpotential and long lifetime. The remarkable properties arises from the introduced multiple heteroatom dopants and stable 3D hierarchical structure with multi-scale pores, which provides the abundant uniform high-active S and N species and efficient charge transfer as well as mass transportation. These results demonstrate the potential strategy in developing suitable carbon-based bi-/multi-functional catalysts to enable the next generation of the rechargeable metal-air batteries.
基金support from the National Natural Science Foundation of China(Nos.51575135,51622503,U1537206,and 51621091)is highly appreciated.
文摘Rational design of efficient bifunctional electrocatalysts is highly imperative but still a challenge for overall water splitting.Herein,we construct novel freestanding Mo-doped NiCoP nanosheet arrays by the hydrothermal and phosphation processes,serving as bifunctional electrocatalysts for overall water splitting.Notably,Mo doping could effectively modulate the electronic structure of NiCoP,leading to the increased electroactive site and improved intrinsic activity of each site.Furthermore,an electrochemical activation strategy is proposed to form Mo-doped(Ni,Co)OOH to fully boost the electrocatalytic activities for oxygen evolution reaction.Benefiting from the unique freestanding structure and Mo doping,Mo-doped NiCoP and(Ni,Co)OOH show the remarkable electrochemical performances,which are competitive among current researches.In addition,an overall water splitting device assembled by both electrodes only requires a cell voltage of 1.61 V to reach a current density of 10 mA cm?2.Therefore,this work opens up new avenues for designing nonprecious bifunctional electrocatalysts by Mo doping and in situ electrochemical activation.
基金supported by the Shandong Provincial Key research and development plan,China(Grant No.2017GGX40119)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2019MB033,ZR2015BM002)the Program of the Qingdao Key Lab of solar energy utilization and energy storage technology(Grant No.QDKLSE201602)。
文摘The rational design and development of cost-effective,high-performance,and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts are essential for rechargeable zinc-air batteries.Herein,a novel FeCo composite composed of alloy nanoparticles embedded in an N,S dual-doped carbon matrix(FeCo/NSC)was prepared via one-step carbonization of amphiphilic dodecanethiol-metal salts wrapped in carbon nitride(C_(3)N_(4)).The compact combination of dual metalalloys and dual-doped carbon endowed the composite with the active sites for the ORR and OER,achieving efficient electrical transmission and highly efficient bifunctional catalytic performance.The obtained FeCo-1/NSC catalyst exhibited excellent electrocatalytic activity with a half-wave potential of 0.82 V(vs.RHE)for the ORR and a low overpotential of 0.325 V at 10 mA cm^(-2) for the OER.The liquid Zn-air battery with FeCo-1/NSC as an air electrode displayed excellent charge-discharge performance,high power density,and robust charge-discharge stability for 150 h compared to the 20%Pt/C+RuO_(2) counterpart.Furthermore,the FeCo-1/NSC-based flexible solid-state Zn-air battery exhibited a higher power density and good charge-discharge stability over 10 h of operation.Thus,a promising strategy for bifunctional electrocatalyst development as part of rechargeable and wearable Zn-air batteries was provided.