Enhancing Photocatalytic Hydrogen Evolution through Electronic Structure and Wettability Adjustment of ZnIn_(2)S_(4)/Bi_(2)O_(3) S-Scheme Heterojunction

The production of renewable fuels through water splitting via photocatalytic hydrogen production holds significant promise.Nonetheless,the sluggish kinetics of hydrogen evolution and the inadequate water adsorption on photocatalysts present notable challenges.In this study,we have devised a straightforward hydrothermal method to synthesize Bi_(2)O_(3)(BO)derived from metal‐organic frameworks(MOFs),loaded with flower-like ZnIn_(2)S_(4)(ZIS).This approach substantially enhances water adsorption and surface catalytic reactions,resulting in a remarkable enhancement of photocatalytic activity.By employing triethanolamine(TEOA)as a sacrificial agent,the hydrogen evolution rate achieved with 15%(mass fraction)ZIS loading on BO reached an impressive value of 1610μmol∙h^(−1)∙g^(−1),marking a 6.34-fold increase compared to that observed for bare BO.Furthermore,through density functional theory(DFT)and ab initio molecular dynamics(AIMD)calculations,we have identified the reactions occurring at the ZIS/BO S-scheme heterojunction interface,including the identification of active sites for water adsorption and catalytic reactions.This study provides valuable insights into the development of high-performance composite photocatalytic materials with tailored electronic properties and wettability.

Reversed charge transfer induced by nickel in Fe-Ni/Mo_(2)C@nitrogen-doped carbon nanobox for promoted reversible oxygen electrocatalysis

The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic performance.In this study,we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system.Specifically,electrons were transferred from the metal-based species to N-doped carbon,while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel.This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo_(2)C@nitrogen-doped carbon catalyst,with a half-wave potential of 0.91 V towards oxygen reduction reaction(ORR)and a low overpotential of 290 m V at 10 mA cm^(-2)towards oxygen evolution reaction(OER)under alkaline conditions.Additionally,the Fe-Ni/Mo_(2)C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h g_(Zn)~(-1))and excellent cycling stability(200 h)in a Zn-air battery.Theoretical calculations revealed that Mo_(2)C effectively inhibited charge transfer from Fe to the support,while secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy region.This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and OER.Consequently,our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.

Boron modulating electronic structure of FeN4C to initiate high-efficiency oxygen reduction reaction and high-performance zinc-air battery

The biggest challenge is to develop a low cost and readily available catalyst to replace expensive commercial Pt/C for efficient electrochemical oxygen reduction reaction(ORR).In this research,closo-[B_(12)H_(12)]^(2−)and 1,10-phenanthroline-iron complexes were introduced into the porous metal-organic framework by impregnation method,and further annealing treatment achieved the successful anchoring of single-atom-Fe in B-doped CN Matrix(FeN4CB).The ORR activity of FeN4CB is comparable to the widely used commercial 20 wt%Pt/C.Where the half-wave potential(E_(1/2))in alkaline medium up to 0.84 V,and even in the face of challenging ORR in acidic medium,the E_(1/2)of ORR driven by FeN4CB is still as high as 0.81 V.When FeN4CB was used as air cathode,the open circuit voltage of Zn-air battery reaches 1.435 V,and the power density and specific capacity are as high as 177 mW cm^(−2)and 800 mAh g_(Zn)^(−1)(theoretical value:820 mAh g_(Zn)^(−1)),respectively.The dazzling point of FeN4CB also appears in the high ORR stability,whether in alkaline or acidic media,E_(1/2)and limiting current density are still close to the initial value after 5000 times cycles.After continuously running the charge-discharge test for 220 h,the charge voltage and discharge voltage of the rechargeable zinc-air battery with FeN4CB as the air cathode maintained the initial state.Density functional theory calculations reveals that introducing B atom to Fe–N4–C can adjust the electronic structure to easily break O=O bond and significantly reduce the energy barrier of the rate-determining step resulting in an improved ORR activity.

A high‐performance transition‐metal phosphide electrocatalyst for converting solar energy into hydrogen at 19.6% STH efficiency

The construction of high-efficiency and low-cost non-noble metal bifunctional electrocatalysts for water electrolysis is crucial for commercial large-scale application of hydrogen energy.Here,we report a novel strategy with erbiumdoped NiCoP nanowire arrays in situ grown on conductive nickel foam(Er-NiCoP/NF).Significantly,the developed electrode shows exceptional bifunctional catalytic activity,which only requires overpotentials of 46 and 225 mV to afford a current density of 10 mAcm^(−2) for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER),respectively.Density functional theory calculations reveal that the appropriate Er incorporation into the NiCoP lattice can significantly modulate the electronic structure with the d-band centers of Ni and Co atoms by shifting to lower energies with respect to the Fermi level,and optimize the Gibbs free energies of HER/OER intermediates,thereby accelerating water-splitting kinetics.When assembled as a solar-driven overall water-splitting electrolyzer,the as-prepared electrode shows a high and stable solar-to-hydrogen efficiency of 19.6%,indicating its potential for practical storage of intermittent energy.

Compositional engineering of HKUST-1/sulfidized NiMn-LDH on functionalized MWCNTs as remarkable bifunctional electrocatalysts for water splitting

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.

Remarkably Enhanced Photodegradation of Organic Pollutants by NH_(2)-UiO-66/ZnO Composite under Visible-Light Irradiation

Semiconductor photocatalysis is a novel highly efficient and low-cost method for removing organic pollutants from wastewater.However,the photoreduction performance of semiconductors on organic pollutants is limited due to the weak absorption of visible light caused by its wide band gap and low carrier utilization rate resulting from severe electron-holes recombination.In the present study,flower-like NH_(2)-UiO-66(NU66)/ZnO nanocomposites were prepared using a facile method and exhibited high efficiency under visible light driven photocatalysts.The X-ray diffractometer(XRD),scanning electron microscope(SEM),transmitor electron microscope(TEM),and X-ray photoelectron spectroscopy(XPS)were used to characterize the prepared samples,indicating that NU66/ZnO was successfully synthesized.The photocatalytic activity of the prepared NU66/ZnO nanocomposites was determined by measuring the photodegradation of methylene blue(MB)and malachite green(MG)under visible-light irradiation.The optimal nanocomposite loading of 5%wt NU66 to NU66/ZnO demonstrated the highest photocatalytic activity for the degradation of MB.The photocatalytic activity of a 5%NU66/ZnO composite was approximately 95-fold and 19-fold higher than that of NU66 and ZnO samples,respectively.The enhanced activity of the 5%wt NU66/ZnO nanocomposite was further confirmed through photoelectrochemical analysis.The formation of type II heterojunctions between the counterparts significantly suppressed recombination of the photogenerated charge carriers.Photocatalytic degradation experiments with different quenchers indicated that the effect of superoxide anion radicals(•O_(2)^(−))had a greater effect than the other scavengers.Additionally,the improved photocatalytic mechanism underlying the activity of NU66/ZnO nanocomposites was also explored.These findings establish a basis for development of MOF based heterojunction for photocatalytic organic pollution remediation.

Modulating the degree of O vacancy defects to achieve selective control of electrochemical CO_(2) reduction products

Conversion of CO_(2) into high-value products using electrochemical CO_(2) reduction(ECR)technology is an effective way to alleviate global warming and reach carbon neutrality.The oxygen vacancies in heterogenous catalysis are generally considered as a powerful method to enhance the performance of ECR by promoting CO_(2) adsorption and activation.However,the extent of defects in oxygen vacancies-activity relation has rarely been studied.Herein,we prepared Cu-Cd bimetallic catalysts with adjustable oxygen defect degree by controlling the amount of cadmium addition.Fourier transform infrared spectroscopy characterization results reveal that the formation of oxygen vacancies is attributed to the asymmetric stretching of Cu-O by the addition of cadmium.Electrochemical results show that the oxygen defect degree can modulate the selectivity of ECR products.A low degree of oxygen defects(CuO)is generally associated with lower product Faraday efficiency(FE_(C2)/FE_(C1)≈114%),but overabundant oxygen vacancies(CuO_(2.625)-CdO_(0.375))are not entirely favorable to improving ECR activity(FE_(C2)/FE_(C1)≈125%)and single selectivity,while an appropriate degree of oxygen vacancies(CuO_(2.75)-CdO_(0.25))can facilitate the ECR process toward single product selective production(FE_(C2)/FE_(C1)≈296%).The theoretical calculation showed that the O vacancy formed on CuO and the interface between CdO and CuO were conducive to enhancing the formation of ^(*)COOH intermediate and promoting the generation of ethylene products.This study provides a new approach and insight into the selective production of single products for future industrial applications of ECR.

Ultrafine nano-copper derived from dopamine polymerization&synchronous adsorption achieve electrochemical purification of nitrate to ammonia in complex water environments

Electrochemical-nitrate-reduction-reaction(eNitRR)synthesis of ammonia is an effective way to treat ni-trate wastewater and alleviate the pressure of the Haber-Bosch ammonia production industry.How to develop effective catalysts to electrochemically reduce nitrate to ammonia and purify sewage under com-plex environmental conditions is the focus of current research.Herein,the dopamine polymerization pro-cess and the[(C_(12)H_(8)N_(2))_(2)Cu]^(2+)complex embedding process were run simultaneously in time and space,and ultrafine Cu nanoparticles(Cu/CN)were effectively loaded on nitrogen-doped carbon after heat treat-ment.Using Cu/CN as the catalyst,the ammonia yield rate and Faradaic efficiency of the electrochemical conversion of NO_(3)^(-)to NH_(3)are highly 8984.0μg h^(−1)mg cat.^(−1)and 95.6%,respectively.Even in the face of complex water environments,such as neutral media,acidic media,coexisting ions,and actual nitrate wastewater,nitrate wastewater can be effectively purified to form high value-added ammonia.The strat-egy of simultaneous embedding increases the exposure rate of Cu sites,and the support of CN is also beneficial to reduce the energy barrier of ^(∗)NO_(3)activation.This study rationally designed catalysts that are beneficial to eNitRR,and considered the situation faced by practical applications during the research stage,reducing the performance gap between laboratory exploration and industrial applications.

Construction of ZnO@CDs@Co_(3)O_(4) sandwich heterostructure with multi-interfacial electron-transfer toward enhanced photocatalytic CO_(2) reduction

Photocatalytic conversion of CO_(2) into small-molecule chemical feedstocks can meet the growing demand for energy and alleviate the global warming. Herein, a p-n ZnO@CDs@Co_(3)O_(4) heterojunction with sandwich structure was constructed by calcination method of self-assembled ZIF-8@CDs@ZIF-67. The ZnO@CDs@Co_(3)O_(4) with well-defined interfacial structure exhibited the significantly enhanced photocatalytic CO_(2) reduction activity, and the optimal catalyst indicated the(CO + CH_(4)) evolution rate of 214.53μmol g^(-1)h^(-1) under simulated solar light, which was superior to ZnO, Co_(3)O_(4) and binary ZnO@Co_(3)O_(4).The internal cavity, exposed active sites, multiple interfaces and constructed p-n heterojunction can facilitate the light harvesting and photoexcited electron transfer. Besides, after introduction of CDs placed in the middle layer between ZnO and Co_(3)O_(4), CDs with excellent photoelectric property further promoted charge separation and migration. This work represents an appealing strategy to construct well-defined photocatalysts for boosting CO_(2) photoreduction.

Unlocking the potential of silicon anodes in lithium-ion batteries:A claw-inspired binder with synergistic interface bonding

Binders play a crucial role in enhancing the cycling stability of silicon anodes in next-generation Li-ion batteries.However,traditional linear polymer binders have difficulty withstanding the volume expansion of silicon during cycling.Herein,inspired by the fact that animals’claws can grasp objects firmly,a claw-like taurine-grafted-poly(acrylic acid)binder(Tau-g-PAA)is designed to improve the electrochemical performance of silicon anodes.The synergistic effects of different polar groups(sulfo and carboxyl)in Tau-g-PAA facilitate the formation of multidimensional interactions with silicon nanoparticles and the diffusion of Li ions,thereby greatly improving the stability and rate performance of silicon anodes,which aligns with results from density functional theory(DFT)simulations.As expected,a Tau-g-PAA/Si electrode exhibits excellent cycling performance with a high specific capacity of 1003mAhg−1at 1C(1C=4200mAhg−1)after 300 cycles,and a high rate performance.The design strategy of using polar small molecule-grafted polymers to create claw-like structures could inspire the development of better binders for silicon-based anodes.

Novel BiOBr/Bi2S3 high-low junction prepared by molten salt method for boosting photocatalytic degradation and H_(2)O_(2)production

The molten salt method focuses on improving the crystallinity of synthetic materials and avoiding the high energy consumption of traditional synthesis processes.In this work,a novel BiOBr/Bi_(2)S_(3)high-low junction with large contact area was constructed by the molten salt method combined with the ion exchange strategy.Its unique energy band structure and new charge transfer mechanism realize the rapid migration of photogenerated charges between different components.Specifically,Bi_(2)S_(3)was grown on BiOBr in situ by a high-temperature molten salt reaction.Due to the deep valence band position of BiOBr and the narrow band gap of Bi_(2)S_(3),an intrinsic internal electric field and band bending are produced at the interface,forming a high-low junction photocatalyst with an intimate interface.In addition,the BiOBr/Bi_(2)S_(3)composite maintains a high oxidation potential and produces high and robust photocatalytic oxidation activity.In the molten state,the close binding of BiOBr and Bi_(2)S_(3)can be promoted through the ion-exchange strategy,resulting in excellent photocatalytic degradation rates of bisphenol A and tetracycline and in-situ generation of H_(2)O_(2).Finally,the mechanism of carriers separation and transfer in BiOBr/Bi_(2)S_(3)high-low junction is also discussed.Density functional theory(DFT)results found that the improvement of O_(2)adsorption ability would promote the occurrence of oxygen reduction reaction(ORR),and make positive contributions to the enhanced H_(2)O_(2)production activity.This study will provide a new perspective for broadening the spectral response range of Bi-based photocatalytic materials and preparing high-low junction photocatalysts with dense interface by the molten salt method.

Tri-functional lanthanum-based biochar for efficient phosphorus recovery,bacterial inhibition,and soil fertility enhancement

Excess phosphorus(P)in water can lead to eutrophication and upset ecological balance.In this study,biochar with ultrathin two-dimensional nanosheets from the natural mesocarp of shaddock was chosen as the carrier.The highly dispersed and small particle size of La(OH)_(3) on the surface of the nanosheets(MSBL3)was successfully achieved using chemical impregnation for the adsorption of P in aqueous solution,and the maximum adsorption capacity was 260.0 mg P g^(−1)[La].The differences in surface crystallization of La(OH)_(3) on biochar at different La loadings were analyzed using the high-precision characterization methods.After six adsorption-desorption cycles,MSBL3 retained 76.7%of its initial performance in terms of the P adsorption capacity.The preparation of 1 g of MSBL3 costs about RMB 1,and it could reduce the P concentration in 2.6 ton of Laoyu River water to below the eutrophication threshold;and the inhibitory effect of MSBL3 on the eutrophication of water bodies was confirmed by the growth state of water hyacinth.Furthermore,0.1 M MSBL3 could inhibit Escherichia coli and Staphylococcus aureus up to 98.7%and 85.0%,respectively,which indicates that MSBL3 can be used to recover P from water and also to improve water quality.In addition,the growth of the maize seedlings verified that the P-absorbed MSBL3 waste is a good soil fertilizer and can solve the problem of post-treatment of the adsorbent.In conclusion,MSBL3 prepared in this study is a promising P sorbent for application.

Nanocoating of CsgA protein for enhanced cell adhesion and proliferation

Immune rejection, poor biocompatibility and cytotoxicity have seriously stalled the widespread application of biometallic materials. To overcome these problems, biometallic materials with fast and sufficient osseointegration, antibacterial properties and long-term stability have attracted the attention of researchers worldwide. Surface modification is currently used as a general strategy to develop material coatings that will overcome these challenging requirements and achieve the successful performance of implants. In this study, we proposed a substrate surface-modification strategy based on biofilm Csg A proteins that promote rapid cell attachment, proliferation, and stabilization of the cytoskeleton. Csg A-based nano-coating is easy to fabricate and has superior performance, which is expected to expand the application of medical implants.

Screening promising TM-doped CeO_(2) monolayer for formaldehyde sensor with high sensitivity and selectivity

Developing convenient,fast-response and high-performance formaldehyde detection sensor is significant but challenging.Herein,two CeO_(2) phases(Fm■m and P4_(2)/mnm),three facets(CeO_(2)(100),CeO_(2)(110)and CeO_(2)(111))and three adsorption sites(top,bridge and hollow)are selected as substrate to interact with formaldehyde.Twenty-eight candidated transition metals(TM)are doped on CeO_(2) surfaces to investigate the performance of detecting formaldehyde by density functional theory.It shows that(i)CeO_(2) in a cubic fluorite structure with the space group Fm■m is suitable for formaldehyde adsorption compared with P4_(2)/mnm;(ii)TM-CeO_(2)(100)(TM=Au,Hf,Nb,Ta,Zr)are considered as candidated materials to absorb formaldehyde ascribed to lower adsorption energies.The d-band center,partial density of states,charge density difference and electron localization function are employed to clarify the mechanism of TM-doped CeO_(2) improving the performance of formaldehyde adsorption.It obviously displays that TM doped CeO_(2)(100)changes the d orbit and rearranges electrons resulting in the superior ability to the adsorbed formaldehyde.This work provides theoretical guidance and experimental motivation for the development of novel formaldehyde sensor based on metal oxide semiconductor materials.

Improving performance of ZnO Schottky photodetector by inserting MXenes modified-layer

The development of low-cost and high-performance ZnO Schottky photodetectors (PDs) has drawn intensive attention,but still a challenge due to their poor conductivity and low light utilization efficiency.Here,we introduce Ti_(3)C_(2)T_(X) into ZnO films to fabricate Schottky UV PDs via facile spin-coated method.The fabricated ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film shows outstanding performance on photocurrent,responsivity,noise equivalent power (NEP),normalized detection rate (D~*),and linear dynamic region (LDR),compared with the original Zn O device.The photocurrent is significantly increased by 466%,and the responsivity is improved by one order of magnitude.In addition,it exhibits relatively low NEP (5.99×10^(-11)W),strong D~*(2.53×10~9 Jones),and high LDR (28 dB).The superior performance is ascribed to the enhanced conductivity and light absorption of ZnO film after introduction of Ti_(3)C_(2)T_(X) modification layer,leading to simultaneously faster electron transfer,lower the radiation recombination of electron and holes on the ZnO/Ti_(3)C_(2)T_(X)/ZnO compound film.This work provides a facile way to develop low-cost and highperformance ZnO Schottky PDs.

Modulation of photocatalytic activity of SrBi_(2)Ta_(2)O_(9)nanosheets in NO removal by tuning facets exposure

Photocatalysts with exposure of different crystal facets often show great differences in their photocatalytic activities due to differences in surface atomic arrangement and coordination.Thus,the actual photoreaction mechanism of a specific crystal facet in photocatalysis deserves to be explored.In this paper,as a case study,Sr Bi_(2)Ta_(2)O_(9)photocatalyst with preferential facet exposure was explored for the photocatalytic removal of NO at a ppb level.The efficiency of NO removal was remarkably improved by tuning the crystal exposure facet with high(200)facet exposure ratio.Optimized exposure of(200)crystal facet in Sr Bi_(2)Ta_(2)O_(9)(SBT)by thermal calcination at 800℃(SBT-800)leads to the highest NO removal activity of51%under a 300 W Xe lamp for 20 min;under visible light,SBT 800 achieves a 5-fold enhancement in NO removal efficiency compared to its counterpart,SBT-900.Active species capture experiments prove that the superoxide radical·O_(2)-is the main active species for the photocatalytic removal of NO,and surface selective deposition experiments conclude that(200)is the main electron-rich crystal plane,based on which the results of density functional theory(DFT)computation reveal the Bi O terminated nature of(001)crystal plane,where the models with both Bi O and Ta O terminated(001)planes were created and computated.Mechanistic study reveals that Sr Bi_(2)Ta_(2)O_(9)with a larger exposure of(200)facet provides more active reduction sites,thereby reducing more O_(2)to·O_(2)-,which further oxidizes the adsorbed NO to NO_(2)-/NO_(3)-.The present work underlines the role of facet tuning in the photoactivity modulation for NO removal photocatalytically.

All in one doubly pillared MXene membrane for excellent oil/water separation,pollutant removal,and anti-fouling performance

Given the diversity and complexity of coexisting oil/dyes/heavy metal ions/microorganisms in wastewater and volatile organic compounds(VOCs)in the air,developing separation materials featured in higher separation efficiency and lower energy consumption for oil and water separation,pollutant removal,and anti-fouling is urgently needed,but it remains a major challenge till now.Herein,a multifunctional Ti_(3)C_(2)MXene membrane with unique double pillar support was proposed by liquid phase ultrasonication and vacuum filtration to over-come the above challenge.Introducing cetyl-trimethyl ammonium bromide(CTAB)and calcium chloride/sodium alginate(CaCl_(2)/SA)to the MXene membrane as crossed double pillars and superhydrophilic surface increases the tolerance and wettability of the membrane.The fabricated doubly pillared MXene(d-Ti_(3)C_(2))membrane exhibits superior oil/water(O/W)separation efficiency(99.76%)with flux(1.284 L m^(-2)h^(-1))for canola oil and organic dye removing efficiency for methyl blue(MB)99.85%,malachite green(MG)100%,and methyl violet(MV)99.72%,respectively,which is 1.05,1.44,1.22,and 1.28 fold compared with pre-pillared Ti_(3)C_(2)(p-Ti_(3)C_(2)).The superior anti-oil/dye/fouling is attributed to lower oil conglutination,high hydrophily,and antibacterial activity.The versatile MXene membrane also shows distinguished separation of VOCs(η>99%)from polluted air.The experimental and molecular dynamics(MD)computational simulation results illustrate that the superior sepa-ration efficiency of the Ti_(3)C_(2)MXene membrane is ascribed to the unique doubly pillared space channel.This study paves a new road to further research on one step integration strategy for complex O/W separation,wastewater and VOCs removal,and anti-fouling via tuning nano/macro architecture.