Simultaneously realizing improved activity and stability of acidic oxygen evolution reaction(OER) electrocatalysts is highly promising for developing cost-effective sustainable energy in the splitting of water techniq...Simultaneously realizing improved activity and stability of acidic oxygen evolution reaction(OER) electrocatalysts is highly promising for developing cost-effective sustainable energy in the splitting of water technique.Herein,we report iridium nanocrystals embedded into 3D conductive clothes(Ir-NCT/CC) as a low iridium electrocatalyst realizing ultrahigh acidic OER activity and robust stability.The well-designed Ir-NCT/CC requires a low overpotential of 202 mV to reach the current density of 10 mA cm^(-2)with a high mass activity of 1754 A g^(-1).Importantly,in acidic overall water splitting,Ir-NCT/CC merely delivers a cell voltage of 1.469 V at a typical current density of 10 mA cm^(-2)and also maintains robust durability under continuous operation.We identify that a low working voltage drives the formation of a highly stable amorphous IrOxactive phase over the surface of Ir nanocrystals(surface heterojunction IrOx/Ir-NCT) during operating conditions,which contributes to an effective and durable OER process.展开更多
The use of the internal magnetic field of ferromagnets can effectively promote charge separation and transfer(CST)in photoelectrochemical energy conversion.However,photoelectrochemical materials with a ferromagnetic f...The use of the internal magnetic field of ferromagnets can effectively promote charge separation and transfer(CST)in photoelectrochemical energy conversion.However,photoelectrochemical materials with a ferromagnetic field are scarce,and the internal magnetic field is negligible in nonferromagnetic mate-rials.To address this issue,we propose a rational method for preparing ferromagnetic TiO_(2)powder using controllable oxygen vacancies in anatase TiO_(2)with co-exposed{001}and{101}facets.Accordingly,an ex-cellent saturation magnetisation of 0.0014 emu/g in TiO_(2)is achieved owing to an asymmetric and uneven charge distribution.Compared with that of nonferromagnetic TiO_(2),the efficiency of photocatalytic hydro-gen generation of ferromagnetic TiO_(2)is improved by 0.64 times.The enhancement of photocatalytic hy-drogen generation is due to the different forces exerted on the electrons and holes in the magnetic field,which significantly improve the photogenerated CST efficiency of ferromagnetic TiO_(2).This result high-lights the significant role of the synergistic regulation of the crystal structure and defects in regulating the ferromagnetic characteristics of materials.The findings of this study provide guidance for leveraging point defects to promote CST for high-efficiency solar-energy conversion systems.展开更多
Surface heterojunction engineering has been demonstrated to be an efficient strategy for the spatial charge separation of photocatalysts.As a consequence,the improved photocatalytic activity is highly determined by th...Surface heterojunction engineering has been demonstrated to be an efficient strategy for the spatial charge separation of photocatalysts.As a consequence,the improved photocatalytic activity is highly determined by the atom arrangement and coordination state of a crystallographic plane.A high-index facet exposed with a high density of low-coordination atoms generally displays better catalytic performance than the lowindex one because of its high surface energy.Inspired by the above viewpoints,it is proposed that the construction of a surface heterojunction enclosed by different high-index facets or a mixed form of high-index and low-index facets is a promising avenue to further promote the photocatalytic activity.However,the synthesis of high-index facet based photocatalysts is highly challenging for surface heterojunctions.Herein,we prepare a polyhedral 30-faceted Cu_(2)O microcrystal type-Ⅱ surface heterojunction co-exposed with 24 high-index{332}facets and 6 low-index{001}facets using a capping agent-assisted liquid-phase reduction method.Compared to the common truncated octahedral(14-facet)Cu_(2)O microcrystal coexposed with 8{111}and 6{001}facets,the 30-faceted Cu_(2)O possesses a highly improved photodegradation activity in the case of normalized specific surface area.Density functional theory(DFT)calculations and in situ photodeposition of metal and metal oxide nanoparticle results indicate that the 30-faceted Cu_(2)O microcrystal is a well-matched{332}-{001}type-Ⅱ surface heterojunction,which presents a beneficial pathway for efficient charge separation and more high-activity sites for photo-redox reaction than the truncated octahedral surface heterojunction.This work confirms the spatial charge separation and high-index facet dependence in polyhedral Cu_(2)O surface heterojunctions,which provides theoretical guidance for surface heterojunction engineering to enhance photocatalytic activity.展开更多
Nitrogen-doped anatase TiO 2 microsheets with 65%（001） and 35%（101） exposed faces were fabricated by the hydrothermal method using TiN as precursor in the presence of HF and HCl. The samples were characterized by ...Nitrogen-doped anatase TiO 2 microsheets with 65%（001） and 35%（101） exposed faces were fabricated by the hydrothermal method using TiN as precursor in the presence of HF and HCl. The samples were characterized by scanning electron microscopy,X-ray diffraction,N2 adsorption,X-ray photoelectron spectroscopy,UV-visible spectroscopy,and electrochemical impedance spectroscopy. Their photocatalytic activity was evaluated using the photocatalytic reduction of CO2. The N-doped TiO 2 sample exhibited a much higher visible light photocatalytic activity for CO2 reduction than its precursor TiN and commercial TiO 2（P25）. This was due to the synergistic effect of the formation of surface heterojunctions on the TiO 2 microsheet surface,enhanced visible light absorption by nitrogen-doping,and surface fluorination.展开更多
Rapid recombination of charge carriers and sluggish Cu^(2+)/Cu^(+)conversion rate in Cu-based photocatalysts hinder the improvement of the peroxymonosulfate(PMS)activation efficiency.Herein,a novel S-scheme system was...Rapid recombination of charge carriers and sluggish Cu^(2+)/Cu^(+)conversion rate in Cu-based photocatalysts hinder the improvement of the peroxymonosulfate(PMS)activation efficiency.Herein,a novel S-scheme system was successfully built through hydrothermal and in-situ calcination methods to activate PMS for norfloxacin(NOR)degradation,which combined CuO with BiVO_(4)(BVO)containing surface heterojunc-tion.The UV-vis spectra manifested that BVO displayed excellent visible light absorption performance after compounding with CuO,and the light absorption threshold of CuO/BVO was about 600 nm.Thanks to the existence of surface heterojunction in BVO,the photoinduced electrons,and holes would trans-fer to{010}and{110}facets,respectively.The construction of S-scheme heterojunction further facilitated the accumulation of electrons on CuO,thus realizing the spatial separation of charge carriers.In addi-tion,the electrons gathered on the CuO expedited the Cu^(2+)/Cu^(+)cycle,thereby improving the activation efficiency of PMS.On this basis,the NOR removal capacity of 5CuO/BVO composites was obviously en-hanced,which was 3.65 and 2.45 times that of CuO and BVO.Moreover,the influence of ambient pH and PMS dosage on the photocatalytic performance of CuO/BVO was investigated.Through the analysis of NOR degradation pathways and degradation products,it was found that the toxicity threat of NOR to the environment was reduced during the degradation process.According to the XPS results,forming the S-scheme heterojunction accelerated the Cu^(2+)/Cu^(+)redox cycle during the PMS activating process.Meanwhile,photoluminescence(PL)and time-resolved photoluminescence(TRPL)analysis demonstrated that the CuO/BVO composites exhibited eminent ability for charge separation.The possible mechanism of charge transfer was assumed by exploring reactive species and the energy band structure of catalysts.To sum up,this research provides a new perspective on boosting PMS activation to purify antibiotics in water.展开更多
基金supported by the National Natural Science Foundation of China(12205300 and 12135012)the Natural Science Foundation of Anhui Province(2208085QA28 and 2208085J01)。
文摘Simultaneously realizing improved activity and stability of acidic oxygen evolution reaction(OER) electrocatalysts is highly promising for developing cost-effective sustainable energy in the splitting of water technique.Herein,we report iridium nanocrystals embedded into 3D conductive clothes(Ir-NCT/CC) as a low iridium electrocatalyst realizing ultrahigh acidic OER activity and robust stability.The well-designed Ir-NCT/CC requires a low overpotential of 202 mV to reach the current density of 10 mA cm^(-2)with a high mass activity of 1754 A g^(-1).Importantly,in acidic overall water splitting,Ir-NCT/CC merely delivers a cell voltage of 1.469 V at a typical current density of 10 mA cm^(-2)and also maintains robust durability under continuous operation.We identify that a low working voltage drives the formation of a highly stable amorphous IrOxactive phase over the surface of Ir nanocrystals(surface heterojunction IrOx/Ir-NCT) during operating conditions,which contributes to an effective and durable OER process.
基金the China Postdoctoral Science Foundation(Grant No.2021M701829)It was also sup-ported by the Natural Science Foundation of Gansu Province in China(Grant No.22JR5RA484)+2 种基金Fundamental Research Funds for the Central University(Nos.lzujbky-2021-61 and SWU-KT22001)State Key Laboratory of New Ceramic and Fine Processing Ts-inghua University(No.KF202118)The authors would like to thank Tsinghua-Deqing Joint Research center for Materials Design and Industrial Innovation for the support.The authors would like to thank Shiyanjia Lab(www.shiyanjia.com)for the support provided for hydrogen generation,SS-SPV measurement,ESR test,DFT cal-culations,and modification polish.
文摘The use of the internal magnetic field of ferromagnets can effectively promote charge separation and transfer(CST)in photoelectrochemical energy conversion.However,photoelectrochemical materials with a ferromagnetic field are scarce,and the internal magnetic field is negligible in nonferromagnetic mate-rials.To address this issue,we propose a rational method for preparing ferromagnetic TiO_(2)powder using controllable oxygen vacancies in anatase TiO_(2)with co-exposed{001}and{101}facets.Accordingly,an ex-cellent saturation magnetisation of 0.0014 emu/g in TiO_(2)is achieved owing to an asymmetric and uneven charge distribution.Compared with that of nonferromagnetic TiO_(2),the efficiency of photocatalytic hydro-gen generation of ferromagnetic TiO_(2)is improved by 0.64 times.The enhancement of photocatalytic hy-drogen generation is due to the different forces exerted on the electrons and holes in the magnetic field,which significantly improve the photogenerated CST efficiency of ferromagnetic TiO_(2).This result high-lights the significant role of the synergistic regulation of the crystal structure and defects in regulating the ferromagnetic characteristics of materials.The findings of this study provide guidance for leveraging point defects to promote CST for high-efficiency solar-energy conversion systems.
基金the support of the National Science Foundation of China(NSFC No.51834009,51801151 and U1866203)the Natural Science Foundation of Shaanxi Province(No.2020JZ-47 and 2020JM-451)+4 种基金the Hundred Talent Program of Shaanxi Province,the Key Laboratory Project of Shaanxi Education Department(No.18JS070,18JK0560 and 17JS081)the Shaanxi Province Science Fund for Distinguished Young Scholars(2018JC-027)China Postdoctoral Science Foundation(Grant No.2018M633643XB)the Key Research and Development Project of Shaanxi Province(No.2017ZDXM-GY-033 and 2017ZDXM-GY-028)the Key Laboratory Project of Science and Technology Agency(No.13JS075).
文摘Surface heterojunction engineering has been demonstrated to be an efficient strategy for the spatial charge separation of photocatalysts.As a consequence,the improved photocatalytic activity is highly determined by the atom arrangement and coordination state of a crystallographic plane.A high-index facet exposed with a high density of low-coordination atoms generally displays better catalytic performance than the lowindex one because of its high surface energy.Inspired by the above viewpoints,it is proposed that the construction of a surface heterojunction enclosed by different high-index facets or a mixed form of high-index and low-index facets is a promising avenue to further promote the photocatalytic activity.However,the synthesis of high-index facet based photocatalysts is highly challenging for surface heterojunctions.Herein,we prepare a polyhedral 30-faceted Cu_(2)O microcrystal type-Ⅱ surface heterojunction co-exposed with 24 high-index{332}facets and 6 low-index{001}facets using a capping agent-assisted liquid-phase reduction method.Compared to the common truncated octahedral(14-facet)Cu_(2)O microcrystal coexposed with 8{111}and 6{001}facets,the 30-faceted Cu_(2)O possesses a highly improved photodegradation activity in the case of normalized specific surface area.Density functional theory(DFT)calculations and in situ photodeposition of metal and metal oxide nanoparticle results indicate that the 30-faceted Cu_(2)O microcrystal is a well-matched{332}-{001}type-Ⅱ surface heterojunction,which presents a beneficial pathway for efficient charge separation and more high-activity sites for photo-redox reaction than the truncated octahedral surface heterojunction.This work confirms the spatial charge separation and high-index facet dependence in polyhedral Cu_(2)O surface heterojunctions,which provides theoretical guidance for surface heterojunction engineering to enhance photocatalytic activity.
基金supported by the National Basic Research Program of China(973 Program2013CB632402)+7 种基金the National Natural Science Foundation of China(513201050015137219051402025and 21433007)the Natural Science Foundation of Hubei Province(2015CFA001)the Fundamental Research Funds for the Central Universities(WUT:2014-VII-010)the Self-Determined and Innovative Research Funds of State Key Laboratory of Advanced Technology for Material Synthesis and ProcessingWuhan University of Technology(2013-ZD-1)~~
文摘Nitrogen-doped anatase TiO 2 microsheets with 65%（001） and 35%（101） exposed faces were fabricated by the hydrothermal method using TiN as precursor in the presence of HF and HCl. The samples were characterized by scanning electron microscopy,X-ray diffraction,N2 adsorption,X-ray photoelectron spectroscopy,UV-visible spectroscopy,and electrochemical impedance spectroscopy. Their photocatalytic activity was evaluated using the photocatalytic reduction of CO2. The N-doped TiO 2 sample exhibited a much higher visible light photocatalytic activity for CO2 reduction than its precursor TiN and commercial TiO 2（P25）. This was due to the synergistic effect of the formation of surface heterojunctions on the TiO 2 microsheet surface,enhanced visible light absorption by nitrogen-doping,and surface fluorination.
基金the financial support of this work from the National Natural Science Foundation of China(Grant No.22172064)National Laboratory of Solid State Microstructures,Nanjing University(Grant No.M34047)+1 种基金Project of Wuxi Science and Technology Development Fund(Grant No.Y20212004)Prof.Haifeng Shi was indebted to the financial support from the Qing Lan Project of Jiangsu Province.
文摘Rapid recombination of charge carriers and sluggish Cu^(2+)/Cu^(+)conversion rate in Cu-based photocatalysts hinder the improvement of the peroxymonosulfate(PMS)activation efficiency.Herein,a novel S-scheme system was successfully built through hydrothermal and in-situ calcination methods to activate PMS for norfloxacin(NOR)degradation,which combined CuO with BiVO_(4)(BVO)containing surface heterojunc-tion.The UV-vis spectra manifested that BVO displayed excellent visible light absorption performance after compounding with CuO,and the light absorption threshold of CuO/BVO was about 600 nm.Thanks to the existence of surface heterojunction in BVO,the photoinduced electrons,and holes would trans-fer to{010}and{110}facets,respectively.The construction of S-scheme heterojunction further facilitated the accumulation of electrons on CuO,thus realizing the spatial separation of charge carriers.In addi-tion,the electrons gathered on the CuO expedited the Cu^(2+)/Cu^(+)cycle,thereby improving the activation efficiency of PMS.On this basis,the NOR removal capacity of 5CuO/BVO composites was obviously en-hanced,which was 3.65 and 2.45 times that of CuO and BVO.Moreover,the influence of ambient pH and PMS dosage on the photocatalytic performance of CuO/BVO was investigated.Through the analysis of NOR degradation pathways and degradation products,it was found that the toxicity threat of NOR to the environment was reduced during the degradation process.According to the XPS results,forming the S-scheme heterojunction accelerated the Cu^(2+)/Cu^(+)redox cycle during the PMS activating process.Meanwhile,photoluminescence(PL)and time-resolved photoluminescence(TRPL)analysis demonstrated that the CuO/BVO composites exhibited eminent ability for charge separation.The possible mechanism of charge transfer was assumed by exploring reactive species and the energy band structure of catalysts.To sum up,this research provides a new perspective on boosting PMS activation to purify antibiotics in water.
