利用一种新的原位水解沉积方法,以在高湿度空气中老化的甲醇中作为溶剂,通过乙醇钽水解而成前驱体微球颗粒沉积,制备出了高效的Ta_3N_5微球光电极,其1.6 V(vs RHE)电极电位下的光电流值达到了6.6 m A·cm^(-2)。相反地,在新鲜的甲...利用一种新的原位水解沉积方法,以在高湿度空气中老化的甲醇中作为溶剂,通过乙醇钽水解而成前驱体微球颗粒沉积,制备出了高效的Ta_3N_5微球光电极,其1.6 V(vs RHE)电极电位下的光电流值达到了6.6 m A·cm^(-2)。相反地,在新鲜的甲醇溶液中没有钽前驱体微球颗粒沉积。这表明甲醇中水的含量对Ta_3N_5微球光电极的形成十分重要。另外,本制备方法也能方便地在其他透明导电衬底上制备出Ta_3N_5。展开更多
将MoS2电催化剂担载在InP光阴极表面,提升了InP光阴极光电化学分解水产氢性能,确定了最优的MoS2电催化剂担载电量为15 mC·cm-2;在担载前后,开启电势由-100 mV移动至120 mV;在-0.35 V vs RHE时,电流密度由15 mA·cm-2提升至43 m...将MoS2电催化剂担载在InP光阴极表面,提升了InP光阴极光电化学分解水产氢性能,确定了最优的MoS2电催化剂担载电量为15 mC·cm-2;在担载前后,开启电势由-100 mV移动至120 mV;在-0.35 V vs RHE时,电流密度由15 mA·cm-2提升至43 mA·cm-2。另外,通过改变入射光强和加入电子牺牲剂的方法进一步研究了MoS2担载InP光阴极产氢反应的限制步骤为光生电子与空穴在InP表面的复合。展开更多
A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)N...A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)Nb_(3)O_(10) nanosheets.When the sacrificial donor ethylenediaminetetraacetic acid(EDTA)disodium salt dihydrate was used,RuP/Pt/TiO_(2) showed higher activity than RuP/Pt/HCa_(2)Nb_(3)O_(10).In contrast,when NaI(a reversible electron donor)was used,RuP/Pt/TiO_(2) showed little activity due to back electron transfer to the electron acceptor(I_(3)-),which was gener-ated as the oxidation product of I-.By modification with anionic polymers(sodium poly(styrenesulfonate)or sodium polymethacrylate)that could inhibit the scavenging of conduction band electrons by I_(3)-,the H_(2) production activity from aqueous NaI was improved,but it did not exceed that of RuP/Pt/HCa_(2)Nb_(3)O_(10).Transient absorption measurements showed that the rate of semiconductor-to-dye back electron transfer was slower in the case of TiO_(2) than HCa_(2)Nb_(3)O_(10),but the electron transfer reaction to I3-was much faster.These results indicate that Pt/TiO_(2) is useful for reactions with sacrificial reductants(e.g.,EDTA),where the back electron transfer reaction to the more reducible product can be neglected.However,more careful design of the catalyst will be nec-essary when a reversible electron donor is employed.展开更多
Hydrogen production via solar water splitting is regarded as one of the most promising ways to utilize solar energy and has attracted more and more attention. Great progress has been made on photocatalytic water split...Hydrogen production via solar water splitting is regarded as one of the most promising ways to utilize solar energy and has attracted more and more attention. Great progress has been made on photocatalytic water splitting for hydrogen production in the past few years. This review summarizesthe very recent progress (mainly in the last 2–3 years) on three major types of solar hydrogenproduction systems: particulate photocatalysis (PC) systems, photoelectrochemical (PEC) systems,and photovoltaic‐photoelectrochemical (PV‐PEC) hybrid systems. The solar‐to‐hydrogen (STH)conversion efficiency of PC systems has recently exceeded 1.0% using a SrTiO3:La,Rh/Au/BiVO4:Mophotocatalyst, 2.5% for PEC water splitting on a tantalum nitride photoanode, and reached 22.4%for PV‐PEC water splitting using a multi‐junction GaInP/GaAs/Ge cell and Ni electrode hybrid system.The advantages and disadvantages of these systems for hydrogen production via solar watersplitting, especially for their potential demonstration and application in the future, are briefly describedand discussed. Finally, the challenges and opportunities for solar water splitting solutions are also forecasted.展开更多
Solar‐driven thermochemical water splitting represents one efficient route to the generation of H2as a clean and renewable fuel.Due to their outstanding catalytic abilities and promising solar fuel production capacit...Solar‐driven thermochemical water splitting represents one efficient route to the generation of H2as a clean and renewable fuel.Due to their outstanding catalytic abilities and promising solar fuel production capacities,perovskite‐type redox catalysts have attracted significant attention in this regard.In the present study,the perovskite series La1‐xCaxMn1‐yAlyO3(x,y=0.2,0.4,0.6,or0.8)was fabricated using a modified Pechini method and comprehensively investigated to determine the applicability of these materials to solar H2production via two‐step thermochemical water splitting.The thermochemical redox behaviors of these perovskites were optimized by doping at either the A(Ca)or B(Al)sites over a broad range of substitution values,from0.2to0.8.Through this doping,a highly efficient perovskite(La0.6Ca0.4Mn0.6Al0.4O3)was developed,which yielded a remarkable H2production rate of429μmol/g during two‐step thermochemical H2O splitting,going between1400and1000°C.Moreover,the performance of the optimized perovskite was found to be eight times higher than that of the benchmark catalyst CeO2under the same experimental conditions.Furthermore,these perovskites also showed impressive catalytic stability during two‐step thermochemical cycling tests.These newly developed La1‐xCaxMn1‐yAlyO3redox catalysts appear to have great potential for future practical applications in thermochemical solar fuel production.展开更多
Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO...Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.展开更多
Although monoclinic WO3 is widely studied as a prototypical photoanode material for solar water splitting,limited success,hitherto,in fabricating WO3 photoanodes that simultaneously demonstrate high efficiency and rep...Although monoclinic WO3 is widely studied as a prototypical photoanode material for solar water splitting,limited success,hitherto,in fabricating WO3 photoanodes that simultaneously demonstrate high efficiency and reproducibility has been realized.The difficulty in controlling both the efficiency and reproducibility is derived from the ever-changing structures/compositions and chemical environments of the precursors,such as peroxytungstic acid and freshly prepared tungstic acid,which render the fabrication processes of the WO3 photoanodes particularly uncontrollable.Herein,a highly reproducible sol-gel process was developed to establish efficient and translucent WO3 photoanodes using a chemically stable ammonium metatungstate precursor.Under standard simulated sunlight of air mass 1.5 G,100 m W cm-2,the WO3 photoanode delivered photocurrent densities of ca.2.05 and2.25 m A cm^-2at 1.23 V versus the reversible hydrogen electrode(RHE),when tested in 1 mol L^-1H2SO4 and CH3SO3H,respectively.Hence,the WO3 photoanodes fabricated herein are one of the WO3 photoanodes with the highest performance ever reported.The reproducibility of the fabrication scheme was evaluated by testing 50 randomly selected WO3 samples in1 mol L^-1H2SO4,which yielded an average photocurrent density of 1.8 m A cm^-2at 1.23 VRHEwith a small standard deviation.Additionally,the effectiveness of the ammonium metatungstate precursor solution was maintained for at least 3weeks,when compared with the associated upper-limit values of peroxytungstic and tungstic acid-based precursors after 3 d.This study presents a key step to the future development of WO3 photoanodes for efficient solar water splitting.展开更多
Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting dem...Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive （hence low energy density） and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical （PEC） water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.展开更多
文摘利用一种新的原位水解沉积方法,以在高湿度空气中老化的甲醇中作为溶剂,通过乙醇钽水解而成前驱体微球颗粒沉积,制备出了高效的Ta_3N_5微球光电极,其1.6 V(vs RHE)电极电位下的光电流值达到了6.6 m A·cm^(-2)。相反地,在新鲜的甲醇溶液中没有钽前驱体微球颗粒沉积。这表明甲醇中水的含量对Ta_3N_5微球光电极的形成十分重要。另外,本制备方法也能方便地在其他透明导电衬底上制备出Ta_3N_5。
文摘将MoS2电催化剂担载在InP光阴极表面,提升了InP光阴极光电化学分解水产氢性能,确定了最优的MoS2电催化剂担载电量为15 mC·cm-2;在担载前后,开启电势由-100 mV移动至120 mV;在-0.35 V vs RHE时,电流密度由15 mA·cm-2提升至43 mA·cm-2。另外,通过改变入射光强和加入电子牺牲剂的方法进一步研究了MoS2担载InP光阴极产氢反应的限制步骤为光生电子与空穴在InP表面的复合。
基金the financial support from Australian Research Council through its DP and FF programsthe support from Australian Government Research Training Program and UQ Centennial Scholarships
文摘A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)Nb_(3)O_(10) nanosheets.When the sacrificial donor ethylenediaminetetraacetic acid(EDTA)disodium salt dihydrate was used,RuP/Pt/TiO_(2) showed higher activity than RuP/Pt/HCa_(2)Nb_(3)O_(10).In contrast,when NaI(a reversible electron donor)was used,RuP/Pt/TiO_(2) showed little activity due to back electron transfer to the electron acceptor(I_(3)-),which was gener-ated as the oxidation product of I-.By modification with anionic polymers(sodium poly(styrenesulfonate)or sodium polymethacrylate)that could inhibit the scavenging of conduction band electrons by I_(3)-,the H_(2) production activity from aqueous NaI was improved,but it did not exceed that of RuP/Pt/HCa_(2)Nb_(3)O_(10).Transient absorption measurements showed that the rate of semiconductor-to-dye back electron transfer was slower in the case of TiO_(2) than HCa_(2)Nb_(3)O_(10),but the electron transfer reaction to I3-was much faster.These results indicate that Pt/TiO_(2) is useful for reactions with sacrificial reductants(e.g.,EDTA),where the back electron transfer reaction to the more reducible product can be neglected.However,more careful design of the catalyst will be nec-essary when a reversible electron donor is employed.
基金supported by the National Basic Research Program of the Ministry of Science and Technology (973 Program, 2014CB239400)the National Natural Science Foundation of China (21501236, 21673230)Youth Innovation Promotion Association of Chinese Academy of Sciences (2016167)~~
文摘Hydrogen production via solar water splitting is regarded as one of the most promising ways to utilize solar energy and has attracted more and more attention. Great progress has been made on photocatalytic water splitting for hydrogen production in the past few years. This review summarizesthe very recent progress (mainly in the last 2–3 years) on three major types of solar hydrogenproduction systems: particulate photocatalysis (PC) systems, photoelectrochemical (PEC) systems,and photovoltaic‐photoelectrochemical (PV‐PEC) hybrid systems. The solar‐to‐hydrogen (STH)conversion efficiency of PC systems has recently exceeded 1.0% using a SrTiO3:La,Rh/Au/BiVO4:Mophotocatalyst, 2.5% for PEC water splitting on a tantalum nitride photoanode, and reached 22.4%for PV‐PEC water splitting using a multi‐junction GaInP/GaAs/Ge cell and Ni electrode hybrid system.The advantages and disadvantages of these systems for hydrogen production via solar watersplitting, especially for their potential demonstration and application in the future, are briefly describedand discussed. Finally, the challenges and opportunities for solar water splitting solutions are also forecasted.
基金supported by the Australian Research Council(FT120100913)the National Natural Science Foundation of China(51372248,51432009)~~
文摘Solar‐driven thermochemical water splitting represents one efficient route to the generation of H2as a clean and renewable fuel.Due to their outstanding catalytic abilities and promising solar fuel production capacities,perovskite‐type redox catalysts have attracted significant attention in this regard.In the present study,the perovskite series La1‐xCaxMn1‐yAlyO3(x,y=0.2,0.4,0.6,or0.8)was fabricated using a modified Pechini method and comprehensively investigated to determine the applicability of these materials to solar H2production via two‐step thermochemical water splitting.The thermochemical redox behaviors of these perovskites were optimized by doping at either the A(Ca)or B(Al)sites over a broad range of substitution values,from0.2to0.8.Through this doping,a highly efficient perovskite(La0.6Ca0.4Mn0.6Al0.4O3)was developed,which yielded a remarkable H2production rate of429μmol/g during two‐step thermochemical H2O splitting,going between1400and1000°C.Moreover,the performance of the optimized perovskite was found to be eight times higher than that of the benchmark catalyst CeO2under the same experimental conditions.Furthermore,these perovskites also showed impressive catalytic stability during two‐step thermochemical cycling tests.These newly developed La1‐xCaxMn1‐yAlyO3redox catalysts appear to have great potential for future practical applications in thermochemical solar fuel production.
文摘Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.
基金supported by the Ministry of Education(MOE)Tier 1(M4011959 and M4011528)the National Key Research and Development Program of China(2018YFA0209303)+1 种基金the National Natural Science Foundation of China(U1663228 and 51902153)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Although monoclinic WO3 is widely studied as a prototypical photoanode material for solar water splitting,limited success,hitherto,in fabricating WO3 photoanodes that simultaneously demonstrate high efficiency and reproducibility has been realized.The difficulty in controlling both the efficiency and reproducibility is derived from the ever-changing structures/compositions and chemical environments of the precursors,such as peroxytungstic acid and freshly prepared tungstic acid,which render the fabrication processes of the WO3 photoanodes particularly uncontrollable.Herein,a highly reproducible sol-gel process was developed to establish efficient and translucent WO3 photoanodes using a chemically stable ammonium metatungstate precursor.Under standard simulated sunlight of air mass 1.5 G,100 m W cm-2,the WO3 photoanode delivered photocurrent densities of ca.2.05 and2.25 m A cm^-2at 1.23 V versus the reversible hydrogen electrode(RHE),when tested in 1 mol L^-1H2SO4 and CH3SO3H,respectively.Hence,the WO3 photoanodes fabricated herein are one of the WO3 photoanodes with the highest performance ever reported.The reproducibility of the fabrication scheme was evaluated by testing 50 randomly selected WO3 samples in1 mol L^-1H2SO4,which yielded an average photocurrent density of 1.8 m A cm^-2at 1.23 VRHEwith a small standard deviation.Additionally,the effectiveness of the ammonium metatungstate precursor solution was maintained for at least 3weeks,when compared with the associated upper-limit values of peroxytungstic and tungstic acid-based precursors after 3 d.This study presents a key step to the future development of WO3 photoanodes for efficient solar water splitting.
文摘Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive （hence low energy density） and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical （PEC） water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.
