Ti-Fe2O3 photoanode has received widespread attention in photoelectrochemical(PEC)water spilling because of its optimized oxidative and reductive capability of composites catalyst.However,its low efficiency could limi...Ti-Fe2O3 photoanode has received widespread attention in photoelectrochemical(PEC)water spilling because of its optimized oxidative and reductive capability of composites catalyst.However,its low efficiency could limit its development.Herein,in order to improve the efficiency of PEC water spilling,the all-solid-state direct Z-scheme Ti-ZnFe2O4/Ti-Fe2O3(TZFO/Ti-Fe2O3)nanorod arrays composited with the ideal energy band structure are synthesized by modulating the Fermi level of TZFO for PEC water splitting.The photophysical methods in this work,including the Kelvin probe measurement and transient photovoltage spectroscopy(TPV)measurement,are applied to explore the migration behavior of electric charges at the enhanced interface electric field.Finally,the Z-scheme charge transfer mechanism of TZFO/Ti-Fe2O3 photoanode is proved successfully.Benefiting from the desirable charge transfer at interface electric field,the TZFO/Ti-Fe2O3 exhibits the outstanding photocatalytic oxygen evolution reaction(OER)performance,and the photocurrent of 60TZFO/Ti-Fe2O3 photoanode reaches 2.16 mA/cm^2 at 1.23 V vs.reversible hydrogen electrode(RHE),which is three times higher than that of pure Ti-Fe2O3 photoanode.This work provides a facile approach of modulating interface electric field to optimize the Z-scheme charge-transfer process.展开更多
The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification...The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.展开更多
Z-scheme photocatalytic system has been regarded as a popular field of research in photoelectrochemical(PEC)water splitting.Among the many obstacles facing a Z-scheme photocatalytic system,the analysis methods of inte...Z-scheme photocatalytic system has been regarded as a popular field of research in photoelectrochemical(PEC)water splitting.Among the many obstacles facing a Z-scheme photocatalytic system,the analysis methods of interfacial Z-scheme charge transfer still remain a significant challenge.Hence,in this study,CdS/Ti-Fe_(2)O_(3)heterojunction photoanodes are elaborately designed to explore the charge-transfer behavior in PEC water splitting.In this study,photophysical measurements,including the Kelvin probe measurement,surface photovoltage spectroscopy(SPV),and transient photovoltage spectroscopy(TPV),are used to monitor the migration behavior of photogenerated charges at the interface electric field of CdS/Ti-Fe_(2)O_(3)Z-scheme heterojunction photoanodes.The Kelvin probe and SPV measurements demonstrate that CdS/Ti-Fe_(2)O_(3)interfacial driving force favors the rapid transfer of photoexcited electrons to CdS.The double-beam strategy based on TPV indicates that more electrons of Ti-Fe_(2)O_(3)are combined with the holes of CdS owing to the intensive interface electric field.The results of these measurements successfully prove the Z-scheme migration mechanism of CdS/Ti-Fe_(2)O_(3)photoanodes.Benefiting from the desirable charge transfer at the interface electric field,CdS/Ti-Fe_(2)O_(3)photoanodes exhibit superior photocatalytic oxygen evolution reaction performance compared with that of pure Ti-Fe_(2)O_(3).The photocurrent density of the 25CdS/Ti-Fe_(2)O_(3)photoanode reaches 1.94 mA/cm^(2) at 1.23 V versus reversible hydrogen electrode without excess cocatalyst,and it is two times higher than that of pure Ti-Fe_(2)O_(3)photoanode.Therefore,an outstanding strategy is provided in this study to prove the Z-scheme charge-transfer mechanism of photocatalytic systems in PEC water splitting.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.51572106,21773086,21872063).
文摘Ti-Fe2O3 photoanode has received widespread attention in photoelectrochemical(PEC)water spilling because of its optimized oxidative and reductive capability of composites catalyst.However,its low efficiency could limit its development.Herein,in order to improve the efficiency of PEC water spilling,the all-solid-state direct Z-scheme Ti-ZnFe2O4/Ti-Fe2O3(TZFO/Ti-Fe2O3)nanorod arrays composited with the ideal energy band structure are synthesized by modulating the Fermi level of TZFO for PEC water splitting.The photophysical methods in this work,including the Kelvin probe measurement and transient photovoltage spectroscopy(TPV)measurement,are applied to explore the migration behavior of electric charges at the enhanced interface electric field.Finally,the Z-scheme charge transfer mechanism of TZFO/Ti-Fe2O3 photoanode is proved successfully.Benefiting from the desirable charge transfer at interface electric field,the TZFO/Ti-Fe2O3 exhibits the outstanding photocatalytic oxygen evolution reaction(OER)performance,and the photocurrent of 60TZFO/Ti-Fe2O3 photoanode reaches 2.16 mA/cm^2 at 1.23 V vs.reversible hydrogen electrode(RHE),which is three times higher than that of pure Ti-Fe2O3 photoanode.This work provides a facile approach of modulating interface electric field to optimize the Z-scheme charge-transfer process.
基金Project(2009CB724504)supported by the National Basic Research Program of China
文摘The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.
文摘Z-scheme photocatalytic system has been regarded as a popular field of research in photoelectrochemical(PEC)water splitting.Among the many obstacles facing a Z-scheme photocatalytic system,the analysis methods of interfacial Z-scheme charge transfer still remain a significant challenge.Hence,in this study,CdS/Ti-Fe_(2)O_(3)heterojunction photoanodes are elaborately designed to explore the charge-transfer behavior in PEC water splitting.In this study,photophysical measurements,including the Kelvin probe measurement,surface photovoltage spectroscopy(SPV),and transient photovoltage spectroscopy(TPV),are used to monitor the migration behavior of photogenerated charges at the interface electric field of CdS/Ti-Fe_(2)O_(3)Z-scheme heterojunction photoanodes.The Kelvin probe and SPV measurements demonstrate that CdS/Ti-Fe_(2)O_(3)interfacial driving force favors the rapid transfer of photoexcited electrons to CdS.The double-beam strategy based on TPV indicates that more electrons of Ti-Fe_(2)O_(3)are combined with the holes of CdS owing to the intensive interface electric field.The results of these measurements successfully prove the Z-scheme migration mechanism of CdS/Ti-Fe_(2)O_(3)photoanodes.Benefiting from the desirable charge transfer at the interface electric field,CdS/Ti-Fe_(2)O_(3)photoanodes exhibit superior photocatalytic oxygen evolution reaction performance compared with that of pure Ti-Fe_(2)O_(3).The photocurrent density of the 25CdS/Ti-Fe_(2)O_(3)photoanode reaches 1.94 mA/cm^(2) at 1.23 V versus reversible hydrogen electrode without excess cocatalyst,and it is two times higher than that of pure Ti-Fe_(2)O_(3)photoanode.Therefore,an outstanding strategy is provided in this study to prove the Z-scheme charge-transfer mechanism of photocatalytic systems in PEC water splitting.
