Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy ...Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy of dysprosium(Dy) doping,using the unique 4f orbitals of this rare earth element to enhance electrocatalytic activity of MOFs.Our method involves constructing Dy-doped Ni-MOF(Dy@Ni-MOF) nanoneedles on carbon cloth via a Dy-induced valence electronic perturbation approach.Experiments and density functional theory(DFT) calculations reveal that Dy doping can effectively modify the electronic structure of the Ni active centers and foster a strong electronic interaction between Ni and Dy.The resulting benefits include a reduced work function and a closer proximity of the d-band center to the Fermi level,which is conducive to improving electrical conductivity and promoting the adsorption of oxygen-containing intermediates.Furthermore,the Dy@Ni-MOF achieves superhydrophilicity,ensuring effective electrolyte contact and thus accelerating reaction kinetics,Ex-situ and in-situ analysis results manifest Dy_(2)O_(3)/NiOOH as the actual active species.Therefore,Dy@Ni-MOF shows impressive OER performance,significantly surpassing Ni-MOF.Besides,the overall water splitting device with Dy@NiMOF as an anode delivers a low cell voltage of 1.51 V at 10 mA cm^(-2) and demonstrates long-term stability for 100 h,positioning it as a promising substitute for precious metal catalysts.展开更多
Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR)...Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR).Herein,we employ a partial desulfurization strategy to construct a homologous Ru-RuS_(2) heterostructure anchored on hollow mesoporous carbon nanospheres(Ru-RuS_(2)@C).The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field,accelerating charge transfer and boosting conductivity of electrocatalyst.Consequently,Ru-RuS_(2)@C exhibits robust HOR electrocatalytic activity,achieving an exchange current density and mass activity as high as 3.56 mA cm^(-2) and 2.13 mAμg_(Ru)^(-1),respectively.exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts.Surprisingly,Ru-RuS_(2)@C can tolerate 1000 ppm of cO that lacks in Pt/C.Comprehensive analysis reveals that the directional electron transfer across Ru-RuS_(2) heterointerface induces local charge redistribution in interfacial region,which optimizes and balances the adsorption energies of H and OH species,as well as lowers the energy barrier for water formation,thereby promoting theHoR performance.展开更多
Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity.Herein,we present a synthesis of NiSe_(2)-Ce_(2)(CO_(3))_(2)O hetero...Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity.Herein,we present a synthesis of NiSe_(2)-Ce_(2)(CO_(3))_(2)O heterostructure and demonstrate the efficacy of interfacial Ce_(2)(CO_(3))2O in promoting the formation of catalytically active centers to improve oxygen evolution activity.In-situ Raman spectroscopy shows that incorporation of Ce_(2)(CO_(3))2O into NiSe_(2) causes a cathodic shift of the Ni^(2+)→Ni~(3+) transition potential.Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heterogeneous interface accelerates charge transfer process.Furthermore,density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe_(2),which is coupled with Ce_(2)(CO_(3))_(2)O,can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction(OER) kinetics.Consequently,the resultant NiSe_(2)-Ce_(2)(CO_(3))_(2)O electrode exhibits remarkable electrocatalytic performance with low overpotentials(268/304 mV@50/100 mA cm^(-2)) and excellent stability(50 mA cm^(-2) for 120 h) in the alkaline electrolyte.This work emphasizes the significance of modulating the dynamic changes in developing efficient electrocatalyst.展开更多
Construction of oxygen evolution electrocatalysts with abundant oxygen defects and large specific surface areas can significantly improve the conversion efficiency of overall water splitting.Herein,we adopt a controll...Construction of oxygen evolution electrocatalysts with abundant oxygen defects and large specific surface areas can significantly improve the conversion efficiency of overall water splitting.Herein,we adopt a controlled method to prepare oxygen defect-rich double-layer hierarchical porous Co3O4 arrays on nickel foam(DL-Co3O4/NF)for water splitting.The unique array-like structure,crystallinity,porosity,and chemical states have been carefully investigated through SEM,TEM,XRD,BET,and XPS techniques.The designated DL-Co3O4/NF has oxygen defects of up to 67.7%and a large BET surface area(57.4 m2g-1).Electrochemical studies show that the catalyst only requires an overpotential of 256 mV to reach 20 mA cm-2,as well as a small Tafel slope of 60.8 mV dec-1,which is far better than all control catalysts.Besides,the catalyst also demonstrates excellent overall water splitting performance in a two-electrode system and good long-term stability,far superior to most previously reported catalysts.Electrocatalytic mechanisms indicate that abundant oxygen vacancies provide more active sites and good conductivity.At the same time,the unique porous arrays facilitate electrolyte transport and gas emissions,thereby synergistically improving OER catalytic performance.展开更多
Constructing a low cost,and high-efficiency oxygen evolution reaction(OER)electrocatalyst is of great significance for improving the performance of alkaline electrolyzer,which is still suffering from highenergy consum...Constructing a low cost,and high-efficiency oxygen evolution reaction(OER)electrocatalyst is of great significance for improving the performance of alkaline electrolyzer,which is still suffering from highenergy consumption.Herein,we created a porous iron phosphide and tungsten oxide self-supporting electrocatalyst with oxygen-containing vacancies on foam nickel(Fe_(2)P-WO_(2.92)/NF)through a facile insitu growth,etching and phosphating strategies.The sequence-controllable strategy will not only generate oxygen vacancies and improve the charge transfer between Fe_(2)P and WO_(2.92) components,but also improve the catalyst porosity and expose more active sites.Electrochemical studies illustrate that the Fe_(2)P-WO_(2.92)/NF catalyst presents good OER activity with a low overpotential of 267 mV at 100 mA cm^(-2),a small Tafel slope of 46.3 mV dec^(-1),high electrical conductivity,and reliable stability at high current density(100 mA cm^(-2) for over 60 h in 1.0 M KOH solution).Most significantly,the operating cell voltage of Fe_(2)P-WO_(2.92)/NF‖Pt/C is as low as 1.90 V at 400 mA cm^(-2) in alkaline condition,which is one of the lowest reported in the literature.The electrocatalytic mechanism shows that the oxygen vacancies and the synergy between Fe_(2)P and WO_(2.92) can adjust the electronic structure and provide more reaction sites,thereby synergistically increasing OER activity.This work provides a feasible strategy to fabricate high-efficiency and stable non-noble metal OER electrocatalysts on the engineering interface.展开更多
The construction of oxide/metal composite catalysts is a competent means of exploiting the electronic interactions between oxide/metal to enhance catalytic activity.In this work,we construct a novel heterogeneous comp...The construction of oxide/metal composite catalysts is a competent means of exploiting the electronic interactions between oxide/metal to enhance catalytic activity.In this work,we construct a novel heterogeneous composite(Ru/HfO_(2)-NC)with Ru/HfO2nanoparticles nested in nitrogen-doped porous carbon via a zeolitic imidazole frameworks-assisted(ZIF)co-precipitation and calcination approach.In particular,ZIF guides an in-situ construction of nested configuration and confines the scattered nanoparticles.Strikingly,Ru/HfO_(2)-NC exhibits unusual ORR activity,superb durability,and methanol tolerance in0.1 M KOH solution with high half-wave potential(E1/2)of 0.83 V and follows a near-4e-reaction pathway.Additionally,the ZAB assembled with cathodic Ru/HfO_(2)-NC outputs a power density of 157.3 m W cm^(-2),a specific capacity of 775 mA h g-1Zn,and a prolonged lifespan of 258 h at 5 mA cm^(-2).Meanwhile,the catalyst has demonstrated potential applicability in flexible ZAB.As suggested by experimental results and density functional theory(DFT)analysis,the remarkable property possibly originated from the optimization of the adsorption and desorption of reactive intermediates caused by the reconfiguration of the electronic structure between Ru and HfO_(2).展开更多
As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein...As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal method.Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV dec-1.Additionally,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M KOH.Furthermore,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported catalysts.The excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni species.The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.展开更多
Surface vacancy defects,as the bridge between theoretical structural study and the design of heterogenous catalysts,have captured much attention.This work develops a metal-organic framework-engaged replacement-pyrolys...Surface vacancy defects,as the bridge between theoretical structural study and the design of heterogenous catalysts,have captured much attention.This work develops a metal-organic framework-engaged replacement-pyrolysis approach to obtain highly dispersed Ru nanoparticles immobilized on the vacancy-rich Ni-NiO@C hollow microsphere(Ru/Ni-NiO@C).Fine annealing at 400°C introduces nickel and oxygen vacancies on Ru/Ni-NiO@C surface,resulting in an improved electrical conductivity and rapid mass-charge transfer efficiency.Ru/Ni-NiO@C with a hollow micro/nanostructure and interconnected meso-porosity favors the maximal exposure of abundant active sites and elevation of hydrogen oxidation reaction(HOR)activity.Experimental results and density functional theory(DFT)calculations reveal that an electronic effect between Ru and Ni-NiO@C,in conjunction with nickel/oxygen vacancies in the NiO species could synergistically optimize hydrogen binding energy(HBE)and hydroxide binding energy(OHBE).The HBE and OHBE optimizations thus created confer Ru/Ni-NiO@C with a mass activity over 7.75 times higher than commercial Pt/C.Our work may provide a constructive route to make a breakthrough in elevating the hydrogen electrocatalytic performance.展开更多
Application of transition metal boride(TMB) catalysts towards hydrolysis of NaBH_(4) holds great significance to help relieve the energy crisis. Herein, we present a facile and versatile metal-organic framework(MOF) a...Application of transition metal boride(TMB) catalysts towards hydrolysis of NaBH_(4) holds great significance to help relieve the energy crisis. Herein, we present a facile and versatile metal-organic framework(MOF) assisted strategy to prepare Co_(2)B-CoPO_x with massive boron vacancies by introducing phytic acid(PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67 into cobalt boride. The PA etching effectively breaks down the structure of ZIF-67 to create more vacancies, favoring the maximal exposure of active sites and elevation of catalytic activity. Experimental results demonstrate a drastic electronic interaction between Co and the dopant phosphorous(P), thereby the robustly electronegative P induces electron redistribution around the metal species, which facilitates the dissociation of B-H bond and the adsorption of H_(2)O molecules. The vacancy-rich Co_(2)B-CoPO_x catalyst exhibits scalable performance, characterized by a high hydrogen generation rate(HGR) of 7716.7 m L min^(-1)g^(-1) and a low activation energy(Ea) of 44.9 k J/mol, rivaling state-of-the-art catalysts. This work provides valuable insights for the development of advanced catalysts through P doping and boron vacancy engineering and the design of efficient and sustainable energy conversion systems.展开更多
Most advanced hydrogen evolution reaction(HER)catalysts show high activity under alkaline conditions.However,the performance deteriorates at a natural and acidic pH,which is often problematic in practical applications...Most advanced hydrogen evolution reaction(HER)catalysts show high activity under alkaline conditions.However,the performance deteriorates at a natural and acidic pH,which is often problematic in practical applications.Herein,a rhenium(Re)sulfide–transition-metal dichalcogenide heterojunc-tion catalyst with Re-rich vacancies(NiS_(2)-ReS_(2)-V)has been constructed.The optimized catalyst shows extraordinary electrocatalytic HER performance over a wide range of pH,with ultralow overpotentials of 42,85,and 122 mV under alkaline,acidic,and neutral conditions,respectively.Moreover,the two-electrode system with NiS_(2)-ReS_(2)-V1 as the cathode provides a voltage of 1.73 V at 500 mA cm^(-2),superior to industrial systems.Besides,the open-circuit voltage of a single Zn–H_(2)O cell with NiS_(2)-ReS_(2)-V1 as the cathode can reach an impressive 90.9% of the theoretical value,with a maximum power density of up to 31.6 mW cm^(-2).Moreover,it shows remarkable stability,with sustained discharge for approximately 120 h at 10 mA cm^(-2),significantly outperforming commercial Pt/C catalysts under the same conditions in all aspects.A series of systematic characterizations and theoretical calculations demonstrate that Re vacancies on the heterojunction interface would generate a stronger built-in electric field,which profoundly affects surface charge distribution and subsequently enhances HER performance.展开更多
Hydrogen is one of the most promising energy carriers to replace fossil fuels and electrolyzing water to produce hydrogen is a very effective method.However,designing highly active and stable non-precious metal hydrog...Hydrogen is one of the most promising energy carriers to replace fossil fuels and electrolyzing water to produce hydrogen is a very effective method.However,designing highly active and stable non-precious metal hydrogen evolution electrocatalysts that can be used in universal pH is a huge challenge.Here,we have reported a simple strategy to develop a highly active and durable non-precious MoO2-Ni electrocatalyst for hydrogen evolution reaction(HER)in a wide pH range.The MoO2-Ni catalyst exhibits a superior electrocatalytic performance with low overpotentials of 46,69,and 84 mV to reach-10 mA cm-2 in 1.0 M KOH,0.5 M H2SO4,and 1.0 M PBS electrolytes,respectively.At the same time,the catalyst also shows outstanding stability over a wide pH range.It is particularly noted that the catalytic performance of MoO2-Ni in alkaline solution is comparable to the highest performing catalysts reported.The outstanding HER performance is mainly attributed to the collective effect of the rational morphological design,electronic structure engineering,and strong interfacial coupling between MoO2 and Ni in heterojunctions.This work provides a viable method for the synthesis of inexpensive and efficient HER electrocatalysts for the use in wide pH ranges.展开更多
A hybrid heterojunction-based photocatalyst is synthesized by an electrostatic self-assembly strategy including surface modification and controlled metal deposition.The interfacial contact was made by mixing negativel...A hybrid heterojunction-based photocatalyst is synthesized by an electrostatic self-assembly strategy including surface modification and controlled metal deposition.The interfacial contact was made by mixing negatively charged anatase TiO_(2) nanoparticles with positively charged g-C3N4.Visible-light deposition of Pd nanoparticles largely on TiO_(2) was made possible due to the charge transfer from C_(3)N_(4)(excited by visible light)to the conduction band of TiO_(2) reducing Pd ions on contact with its surface.In order to further test the efficiency of this cascade of electron transfer across the conduction bands of the two semiconductors,photocatalytic H2 production from water was studied.Upon optimizing the ratio of the two semiconductors,increased H2 production rates were observed and attributed to enhanced charge separation.Catalysts were studied by a variety of techniques in order to probe into their properties and link them to activity.The reaction rate,under visible-light excitation,of the best sample showed an 8-fold enhancement when compared to that of Pd-C_(3)N_(4) in identical conditions and the highest apparent quantum yield of 31%was achieved by a 0.1% Pd/20%TiO_(2)/C_(3)N_(4) sample in a 420-to 443-nm range.展开更多
The developing high-efficiency urea fuel cells have an irreplaceable role in solving the increasingly severe environmental crisis and energy shortages.The sluggish six-electron dynamic anodic oxidation reaction is the...The developing high-efficiency urea fuel cells have an irreplaceable role in solving the increasingly severe environmental crisis and energy shortages.The sluggish six-electron dynamic anodic oxidation reaction is the bottleneck of the rapid progress of urea fuel-cell technology.To tackle this challenge,we select the NiCr bimetallic system due to the unique synergic effect between the Ni and the Cr.Moreover,better conductivity is assured using carbon nanotubes(CNTs)as the support.Most importantly,we use a simple hydrothermal method in catalyst preparation for easy scale-up at a low cost.The results show that the hybrid catalysts of NiCr_(x)-oxide-CNTs with different Ni/Cr ratios show much better catalytic performance in terms of active surface area and current density as compared to that of Ni-hydro-CNTs.The optimized NiCr_(2)-oxide-CNTs catalyst exhibits not only the largest electrochemically active surface area(ESA,50.7 m^(2) g^(−1))and the highest urea electrocatalytic current density(115.6 mA cm^(−2)),but also outstanding long-term stability.The prominent performance of the NiCr_(2)-oxide-CNTs catalyst is due to the combined effect of the improved charge transfer between Ni and Cr species,the large ESA,along with an elegant balance between the oxygen-defect sites and hydrophilicity.Moreover,we have proposed a synergistically enhanced urea catalytic mechanism.展开更多
基金supported by the National Natural Science Foundation of China(52363028,21965005)the Natural Science Foundation of Guangxi Province(2021GXNSFAA076001)the Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20297039)。
文摘Tackling the problem of poor conductivity and catalytic stability of pristine metal-organic frameworks(MOFs) is crucial to improve their oxygen evolution reaction(OER) performance.Herein,we introduce a novel strategy of dysprosium(Dy) doping,using the unique 4f orbitals of this rare earth element to enhance electrocatalytic activity of MOFs.Our method involves constructing Dy-doped Ni-MOF(Dy@Ni-MOF) nanoneedles on carbon cloth via a Dy-induced valence electronic perturbation approach.Experiments and density functional theory(DFT) calculations reveal that Dy doping can effectively modify the electronic structure of the Ni active centers and foster a strong electronic interaction between Ni and Dy.The resulting benefits include a reduced work function and a closer proximity of the d-band center to the Fermi level,which is conducive to improving electrical conductivity and promoting the adsorption of oxygen-containing intermediates.Furthermore,the Dy@Ni-MOF achieves superhydrophilicity,ensuring effective electrolyte contact and thus accelerating reaction kinetics,Ex-situ and in-situ analysis results manifest Dy_(2)O_(3)/NiOOH as the actual active species.Therefore,Dy@Ni-MOF shows impressive OER performance,significantly surpassing Ni-MOF.Besides,the overall water splitting device with Dy@NiMOF as an anode delivers a low cell voltage of 1.51 V at 10 mA cm^(-2) and demonstrates long-term stability for 100 h,positioning it as a promising substitute for precious metal catalysts.
基金financially supported by the National Natural Science Foundation of China (52363028)the Natural Science Foundation of Guangxi Province (2021GXNSFAA076001)the Guangxi Technology Base and Talent Subject (GUIKE AD23023004,GUIKE AD20297039)
文摘Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR).Herein,we employ a partial desulfurization strategy to construct a homologous Ru-RuS_(2) heterostructure anchored on hollow mesoporous carbon nanospheres(Ru-RuS_(2)@C).The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field,accelerating charge transfer and boosting conductivity of electrocatalyst.Consequently,Ru-RuS_(2)@C exhibits robust HOR electrocatalytic activity,achieving an exchange current density and mass activity as high as 3.56 mA cm^(-2) and 2.13 mAμg_(Ru)^(-1),respectively.exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts.Surprisingly,Ru-RuS_(2)@C can tolerate 1000 ppm of cO that lacks in Pt/C.Comprehensive analysis reveals that the directional electron transfer across Ru-RuS_(2) heterointerface induces local charge redistribution in interfacial region,which optimizes and balances the adsorption energies of H and OH species,as well as lowers the energy barrier for water formation,thereby promoting theHoR performance.
基金financially National Natural Science Foundation of China (52363028, 21965005)Volkswagen Foundation (Freigeist Fellowship 89592)+2 种基金Natural Science Foundation of Guangxi Province (2021GXNSFAA076001)Guangxi Technology Base and Talent Subject (GUIKE AD23023004, GUIKE AD20297039)Innovation Project of Guangxi Graduate Education (Nos. YCSW2024219, YCBZ2024082)。
文摘Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity.Herein,we present a synthesis of NiSe_(2)-Ce_(2)(CO_(3))_(2)O heterostructure and demonstrate the efficacy of interfacial Ce_(2)(CO_(3))2O in promoting the formation of catalytically active centers to improve oxygen evolution activity.In-situ Raman spectroscopy shows that incorporation of Ce_(2)(CO_(3))2O into NiSe_(2) causes a cathodic shift of the Ni^(2+)→Ni~(3+) transition potential.Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heterogeneous interface accelerates charge transfer process.Furthermore,density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe_(2),which is coupled with Ce_(2)(CO_(3))_(2)O,can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction(OER) kinetics.Consequently,the resultant NiSe_(2)-Ce_(2)(CO_(3))_(2)O electrode exhibits remarkable electrocatalytic performance with low overpotentials(268/304 mV@50/100 mA cm^(-2)) and excellent stability(50 mA cm^(-2) for 120 h) in the alkaline electrolyte.This work emphasizes the significance of modulating the dynamic changes in developing efficient electrocatalyst.
基金supported by the National Natural Science Foundation of China (no.21965005)Natural Science Foundation of Guangxi Province (2018GXNSFAA294077, 2018GXNSFAA281220)+1 种基金Project of High-Level Talents of Guangxi (FKA18015, 2018ZD004)Innovation Project of Guangxi Graduate Education (XYCSZ2019056, YCBZ2019031)。
文摘Construction of oxygen evolution electrocatalysts with abundant oxygen defects and large specific surface areas can significantly improve the conversion efficiency of overall water splitting.Herein,we adopt a controlled method to prepare oxygen defect-rich double-layer hierarchical porous Co3O4 arrays on nickel foam(DL-Co3O4/NF)for water splitting.The unique array-like structure,crystallinity,porosity,and chemical states have been carefully investigated through SEM,TEM,XRD,BET,and XPS techniques.The designated DL-Co3O4/NF has oxygen defects of up to 67.7%and a large BET surface area(57.4 m2g-1).Electrochemical studies show that the catalyst only requires an overpotential of 256 mV to reach 20 mA cm-2,as well as a small Tafel slope of 60.8 mV dec-1,which is far better than all control catalysts.Besides,the catalyst also demonstrates excellent overall water splitting performance in a two-electrode system and good long-term stability,far superior to most previously reported catalysts.Electrocatalytic mechanisms indicate that abundant oxygen vacancies provide more active sites and good conductivity.At the same time,the unique porous arrays facilitate electrolyte transport and gas emissions,thereby synergistically improving OER catalytic performance.
基金supported by the National Natural Science Foundation of China(no.21965005)the Natural Science Foundation of Guangxi Province(2018GXNSFAA294077,2021GXNSFAA076001)+1 种基金the Project of High-Level Talents of Guangxi(F-KA18015)Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20297039)。
文摘Constructing a low cost,and high-efficiency oxygen evolution reaction(OER)electrocatalyst is of great significance for improving the performance of alkaline electrolyzer,which is still suffering from highenergy consumption.Herein,we created a porous iron phosphide and tungsten oxide self-supporting electrocatalyst with oxygen-containing vacancies on foam nickel(Fe_(2)P-WO_(2.92)/NF)through a facile insitu growth,etching and phosphating strategies.The sequence-controllable strategy will not only generate oxygen vacancies and improve the charge transfer between Fe_(2)P and WO_(2.92) components,but also improve the catalyst porosity and expose more active sites.Electrochemical studies illustrate that the Fe_(2)P-WO_(2.92)/NF catalyst presents good OER activity with a low overpotential of 267 mV at 100 mA cm^(-2),a small Tafel slope of 46.3 mV dec^(-1),high electrical conductivity,and reliable stability at high current density(100 mA cm^(-2) for over 60 h in 1.0 M KOH solution).Most significantly,the operating cell voltage of Fe_(2)P-WO_(2.92)/NF‖Pt/C is as low as 1.90 V at 400 mA cm^(-2) in alkaline condition,which is one of the lowest reported in the literature.The electrocatalytic mechanism shows that the oxygen vacancies and the synergy between Fe_(2)P and WO_(2.92) can adjust the electronic structure and provide more reaction sites,thereby synergistically increasing OER activity.This work provides a feasible strategy to fabricate high-efficiency and stable non-noble metal OER electrocatalysts on the engineering interface.
基金supported by the National Natural Science Foundation of China(21965005)the Natural Science Foundation of Guangxi Province(2021GXNSFAA076001)+1 种基金the Project of HighLevel Talents of Guangxi(F-KA18015)Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20297039)。
文摘The construction of oxide/metal composite catalysts is a competent means of exploiting the electronic interactions between oxide/metal to enhance catalytic activity.In this work,we construct a novel heterogeneous composite(Ru/HfO_(2)-NC)with Ru/HfO2nanoparticles nested in nitrogen-doped porous carbon via a zeolitic imidazole frameworks-assisted(ZIF)co-precipitation and calcination approach.In particular,ZIF guides an in-situ construction of nested configuration and confines the scattered nanoparticles.Strikingly,Ru/HfO_(2)-NC exhibits unusual ORR activity,superb durability,and methanol tolerance in0.1 M KOH solution with high half-wave potential(E1/2)of 0.83 V and follows a near-4e-reaction pathway.Additionally,the ZAB assembled with cathodic Ru/HfO_(2)-NC outputs a power density of 157.3 m W cm^(-2),a specific capacity of 775 mA h g-1Zn,and a prolonged lifespan of 258 h at 5 mA cm^(-2).Meanwhile,the catalyst has demonstrated potential applicability in flexible ZAB.As suggested by experimental results and density functional theory(DFT)analysis,the remarkable property possibly originated from the optimization of the adsorption and desorption of reactive intermediates caused by the reconfiguration of the electronic structure between Ru and HfO_(2).
文摘As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal method.Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV dec-1.Additionally,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M KOH.Furthermore,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported catalysts.The excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni species.The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.
基金supported by the National Natural Science Foundation of China(21965005)the Natural Science Foundation of Guangxi Province(2018GXNSFAA294077,2021GXNSFAA076001)+1 种基金the Project of High-Level Talents of Guangxi(F-KA18015)the Guangxi Technology Base and Talent Subject(GUIKEAD18126001,GUIKE AD20297039)。
文摘Surface vacancy defects,as the bridge between theoretical structural study and the design of heterogenous catalysts,have captured much attention.This work develops a metal-organic framework-engaged replacement-pyrolysis approach to obtain highly dispersed Ru nanoparticles immobilized on the vacancy-rich Ni-NiO@C hollow microsphere(Ru/Ni-NiO@C).Fine annealing at 400°C introduces nickel and oxygen vacancies on Ru/Ni-NiO@C surface,resulting in an improved electrical conductivity and rapid mass-charge transfer efficiency.Ru/Ni-NiO@C with a hollow micro/nanostructure and interconnected meso-porosity favors the maximal exposure of abundant active sites and elevation of hydrogen oxidation reaction(HOR)activity.Experimental results and density functional theory(DFT)calculations reveal that an electronic effect between Ru and Ni-NiO@C,in conjunction with nickel/oxygen vacancies in the NiO species could synergistically optimize hydrogen binding energy(HBE)and hydroxide binding energy(OHBE).The HBE and OHBE optimizations thus created confer Ru/Ni-NiO@C with a mass activity over 7.75 times higher than commercial Pt/C.Our work may provide a constructive route to make a breakthrough in elevating the hydrogen electrocatalytic performance.
基金supported by the National Natural Science Foundation of China (No.21965005)Natural Science Foundation of Guangxi Province (No.2021GXNSFAA076001)+1 种基金Guangxi Technology Base and Talent Subject (Nos.GUIKE AD18126001, GUIKE AD20297039)Innovation Project of Guangxi Graduate Education (Nos.YCSW2023140, YCBZ2023062)。
文摘Application of transition metal boride(TMB) catalysts towards hydrolysis of NaBH_(4) holds great significance to help relieve the energy crisis. Herein, we present a facile and versatile metal-organic framework(MOF) assisted strategy to prepare Co_(2)B-CoPO_x with massive boron vacancies by introducing phytic acid(PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67 into cobalt boride. The PA etching effectively breaks down the structure of ZIF-67 to create more vacancies, favoring the maximal exposure of active sites and elevation of catalytic activity. Experimental results demonstrate a drastic electronic interaction between Co and the dopant phosphorous(P), thereby the robustly electronegative P induces electron redistribution around the metal species, which facilitates the dissociation of B-H bond and the adsorption of H_(2)O molecules. The vacancy-rich Co_(2)B-CoPO_x catalyst exhibits scalable performance, characterized by a high hydrogen generation rate(HGR) of 7716.7 m L min^(-1)g^(-1) and a low activation energy(Ea) of 44.9 k J/mol, rivaling state-of-the-art catalysts. This work provides valuable insights for the development of advanced catalysts through P doping and boron vacancy engineering and the design of efficient and sustainable energy conversion systems.
基金This study was supported by the National Research Foundation of Korea(NRF-2021R1A2C4001777,NRF-2022M3H4A1A04096482 and RS-2023-00229679),the National Natural Science Foundation of China(No.21965005,52363028)the Natural Science Foundation of Guangxi Province(2021GXNSFAA076001)the Guangxi Technology Base and Talent Subject(GUIKE AD20297039).
文摘Most advanced hydrogen evolution reaction(HER)catalysts show high activity under alkaline conditions.However,the performance deteriorates at a natural and acidic pH,which is often problematic in practical applications.Herein,a rhenium(Re)sulfide–transition-metal dichalcogenide heterojunc-tion catalyst with Re-rich vacancies(NiS_(2)-ReS_(2)-V)has been constructed.The optimized catalyst shows extraordinary electrocatalytic HER performance over a wide range of pH,with ultralow overpotentials of 42,85,and 122 mV under alkaline,acidic,and neutral conditions,respectively.Moreover,the two-electrode system with NiS_(2)-ReS_(2)-V1 as the cathode provides a voltage of 1.73 V at 500 mA cm^(-2),superior to industrial systems.Besides,the open-circuit voltage of a single Zn–H_(2)O cell with NiS_(2)-ReS_(2)-V1 as the cathode can reach an impressive 90.9% of the theoretical value,with a maximum power density of up to 31.6 mW cm^(-2).Moreover,it shows remarkable stability,with sustained discharge for approximately 120 h at 10 mA cm^(-2),significantly outperforming commercial Pt/C catalysts under the same conditions in all aspects.A series of systematic characterizations and theoretical calculations demonstrate that Re vacancies on the heterojunction interface would generate a stronger built-in electric field,which profoundly affects surface charge distribution and subsequently enhances HER performance.
基金supported by the National Natural Science Foundation of China(21965005)Natural Science Foundation of Guangxi Province(2018GXNSFAA294077 and 2018GXNSFAA281220)Project of High-Level Talents of Guangxi(F-KA18015 and 2018ZD004)。
文摘Hydrogen is one of the most promising energy carriers to replace fossil fuels and electrolyzing water to produce hydrogen is a very effective method.However,designing highly active and stable non-precious metal hydrogen evolution electrocatalysts that can be used in universal pH is a huge challenge.Here,we have reported a simple strategy to develop a highly active and durable non-precious MoO2-Ni electrocatalyst for hydrogen evolution reaction(HER)in a wide pH range.The MoO2-Ni catalyst exhibits a superior electrocatalytic performance with low overpotentials of 46,69,and 84 mV to reach-10 mA cm-2 in 1.0 M KOH,0.5 M H2SO4,and 1.0 M PBS electrolytes,respectively.At the same time,the catalyst also shows outstanding stability over a wide pH range.It is particularly noted that the catalytic performance of MoO2-Ni in alkaline solution is comparable to the highest performing catalysts reported.The outstanding HER performance is mainly attributed to the collective effect of the rational morphological design,electronic structure engineering,and strong interfacial coupling between MoO2 and Ni in heterojunctions.This work provides a viable method for the synthesis of inexpensive and efficient HER electrocatalysts for the use in wide pH ranges.
文摘A hybrid heterojunction-based photocatalyst is synthesized by an electrostatic self-assembly strategy including surface modification and controlled metal deposition.The interfacial contact was made by mixing negatively charged anatase TiO_(2) nanoparticles with positively charged g-C3N4.Visible-light deposition of Pd nanoparticles largely on TiO_(2) was made possible due to the charge transfer from C_(3)N_(4)(excited by visible light)to the conduction band of TiO_(2) reducing Pd ions on contact with its surface.In order to further test the efficiency of this cascade of electron transfer across the conduction bands of the two semiconductors,photocatalytic H2 production from water was studied.Upon optimizing the ratio of the two semiconductors,increased H2 production rates were observed and attributed to enhanced charge separation.Catalysts were studied by a variety of techniques in order to probe into their properties and link them to activity.The reaction rate,under visible-light excitation,of the best sample showed an 8-fold enhancement when compared to that of Pd-C_(3)N_(4) in identical conditions and the highest apparent quantum yield of 31%was achieved by a 0.1% Pd/20%TiO_(2)/C_(3)N_(4) sample in a 420-to 443-nm range.
基金supported by the National Natural Science Foundation of China(21965005)Natural Science Foundation of Guangxi Province(2018GXNSFAA294077,2017GXNSFGA198004)+1 种基金Project of High-Level Talents of Guangxi(F-KA18015,2018ZD004)Innovation Project of Guangxi Graduate Education(XYCSZ2019056,YCBZ2019031).
文摘The developing high-efficiency urea fuel cells have an irreplaceable role in solving the increasingly severe environmental crisis and energy shortages.The sluggish six-electron dynamic anodic oxidation reaction is the bottleneck of the rapid progress of urea fuel-cell technology.To tackle this challenge,we select the NiCr bimetallic system due to the unique synergic effect between the Ni and the Cr.Moreover,better conductivity is assured using carbon nanotubes(CNTs)as the support.Most importantly,we use a simple hydrothermal method in catalyst preparation for easy scale-up at a low cost.The results show that the hybrid catalysts of NiCr_(x)-oxide-CNTs with different Ni/Cr ratios show much better catalytic performance in terms of active surface area and current density as compared to that of Ni-hydro-CNTs.The optimized NiCr_(2)-oxide-CNTs catalyst exhibits not only the largest electrochemically active surface area(ESA,50.7 m^(2) g^(−1))and the highest urea electrocatalytic current density(115.6 mA cm^(−2)),but also outstanding long-term stability.The prominent performance of the NiCr_(2)-oxide-CNTs catalyst is due to the combined effect of the improved charge transfer between Ni and Cr species,the large ESA,along with an elegant balance between the oxygen-defect sites and hydrophilicity.Moreover,we have proposed a synergistically enhanced urea catalytic mechanism.
