以水和氧气为原料,光催化产过氧化氢(H_(2)O_(2))具有绿色、清洁的特点而受到广泛关注。针对氮化碳(g-C_(3)N_(4))本征光催化活性低的问题,本文采用两步热聚合法制备了具有大比表面积和结晶性增强的超薄g-C_(3)N_(4)纳米片光催化剂。煅...以水和氧气为原料,光催化产过氧化氢(H_(2)O_(2))具有绿色、清洁的特点而受到广泛关注。针对氮化碳(g-C_(3)N_(4))本征光催化活性低的问题,本文采用两步热聚合法制备了具有大比表面积和结晶性增强的超薄g-C_(3)N_(4)纳米片光催化剂。煅烧条件对g-C_(3)N_(4)的结构属性和催化性能有显著影响。两步焙烧和1℃·min^(-1)最佳升温速率制备的样品(CN-T-1)表现出显著提高的光催化产H_(2)O_(2)效率(3177.0μmol·g^(-1)·h^(-1)),为一步焙烧和1℃·min^(-1)升温速率制备的样品(CN-O-1)(858.6μmol·g^(-1)·h^(-1))的3.7倍,高于文献报导的纯g-C_(3)N_(4)产H_(2)O_(2)效率。CN-T-1在5次循环使用中H_(2)O_(2)产率先略有下降,后基本保持不变,表现出良好的稳定性。相较于CN-O-1,CN-T-1增强的催化性能归因于更大的比表面积、增强的结晶性、更高氧吸附能力和光生载流子分离效率、更长的载流子寿命,以及超薄片层使其具有更大的带隙(3.07 e V,比CN-O-1大+0.26 e V)和更正的价带位置。·O_(2)^(-)自由基被证实为主要的活性物种。CN-T-1光催化产H_(2)O_(2)被证实为两步单电子ORR路径(O_(2)+e^(-)→·O_(2)^(-)→H_(2)O_(2))。展开更多
V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)i...V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation,which is noted VO-PPyd.The total density of states(TDOS)shows that after the pre-intercalation of PPyd,an intermediate energy level appears between the valence band and conduction band,which provides a step that can effectively reduce the band gap and enhance the electron conductivity.Furthermore,the density functional theory(DFT)results found that Zn^(2+)is more easily de-intercalated from the V-O skeleton,which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn^(2+).Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance(high specific capacity of 465 and 192 mA h g^(-1)at 0.2 and 10 A g^(-1),respectively)and long-term cycling performance(92.7%capacity retention rate after 5300 cycles),due to their advantages in structure and composition.More importantly,the energy density of VO-PPyd//Zn at 581 and 5806 W kg^(-1)is 375 and 247 W h kg^(-1),respectively.VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes,which makes it highly competitive in the field of high-performance cathode materials of AZIBs.展开更多
The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
基金supported by the Natural Science Foundation of China(51572074)Open Fund of Key Laboratory of Drug Analysis and Anti-drug Technology of the Ministry of Public Security(YNPL-B2021002)。
文摘以水和氧气为原料,光催化产过氧化氢(H_(2)O_(2))具有绿色、清洁的特点而受到广泛关注。针对氮化碳(g-C_(3)N_(4))本征光催化活性低的问题,本文采用两步热聚合法制备了具有大比表面积和结晶性增强的超薄g-C_(3)N_(4)纳米片光催化剂。煅烧条件对g-C_(3)N_(4)的结构属性和催化性能有显著影响。两步焙烧和1℃·min^(-1)最佳升温速率制备的样品(CN-T-1)表现出显著提高的光催化产H_(2)O_(2)效率(3177.0μmol·g^(-1)·h^(-1)),为一步焙烧和1℃·min^(-1)升温速率制备的样品(CN-O-1)(858.6μmol·g^(-1)·h^(-1))的3.7倍,高于文献报导的纯g-C_(3)N_(4)产H_(2)O_(2)效率。CN-T-1在5次循环使用中H_(2)O_(2)产率先略有下降,后基本保持不变,表现出良好的稳定性。相较于CN-O-1,CN-T-1增强的催化性能归因于更大的比表面积、增强的结晶性、更高氧吸附能力和光生载流子分离效率、更长的载流子寿命,以及超薄片层使其具有更大的带隙(3.07 e V,比CN-O-1大+0.26 e V)和更正的价带位置。·O_(2)^(-)自由基被证实为主要的活性物种。CN-T-1光催化产H_(2)O_(2)被证实为两步单电子ORR路径(O_(2)+e^(-)→·O_(2)^(-)→H_(2)O_(2))。
基金supported by the National Natural Science Foundation of China (21676036)the Natural Science Foundation of Chongqing (CSTB2023NSCQ-MSX0580)the Graduate Research and Innovation Foundation of Chongqing (CYB22043 and CYS22073)。
文摘V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation,which is noted VO-PPyd.The total density of states(TDOS)shows that after the pre-intercalation of PPyd,an intermediate energy level appears between the valence band and conduction band,which provides a step that can effectively reduce the band gap and enhance the electron conductivity.Furthermore,the density functional theory(DFT)results found that Zn^(2+)is more easily de-intercalated from the V-O skeleton,which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn^(2+).Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance(high specific capacity of 465 and 192 mA h g^(-1)at 0.2 and 10 A g^(-1),respectively)and long-term cycling performance(92.7%capacity retention rate after 5300 cycles),due to their advantages in structure and composition.More importantly,the energy density of VO-PPyd//Zn at 581 and 5806 W kg^(-1)is 375 and 247 W h kg^(-1),respectively.VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes,which makes it highly competitive in the field of high-performance cathode materials of AZIBs.
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
