光电化学水分解电池能够将太阳能直接转化为氢能,是一种理想的太阳能利用方式.p-n叠层电池具有理论转换效率高、成本低廉、材料选择灵活等优势,被认为是最具潜力的一类光电化学水分解电池.然而,目前这类叠层电池的太阳能转化效率还不高...光电化学水分解电池能够将太阳能直接转化为氢能,是一种理想的太阳能利用方式.p-n叠层电池具有理论转换效率高、成本低廉、材料选择灵活等优势,被认为是最具潜力的一类光电化学水分解电池.然而,目前这类叠层电池的太阳能转化效率还不高,主要原因是单个电极的效率太低.本文介绍了几种提高光电极分解水性能的方法—减小光生载流子的体相复合、表面复合以及抑制背反应等,同时综述了国内外关于几种p型半导体光阴极的研究进展,如Si、In P、Cu In1-xGaxS(Se)2、Cu2Zn Sn S4等.通过总结,作者提出一种p-Cu2Zn Sn S4(Cu In1-xGaxS(Se)2)/n-Ta3N5(Fe2O3)组装方式,有望获得高效低成本叠层光电化学水分解电池.展开更多
在众多光阳极材料中,纳米结构材料α-Fe_2O_3由于其光吸收显著、化学稳定性好、储量丰富等优势,被认为是最有前途的材料之一。利用水热法制备了具有良好光解水性能的Co和P掺杂α-Fe_2O_3纳米材料。经过掺杂后α-Fe_2O_3纳米材料仍为纳...在众多光阳极材料中,纳米结构材料α-Fe_2O_3由于其光吸收显著、化学稳定性好、储量丰富等优势,被认为是最有前途的材料之一。利用水热法制备了具有良好光解水性能的Co和P掺杂α-Fe_2O_3纳米材料。经过掺杂后α-Fe_2O_3纳米材料仍为纳米棒状形貌,纳米棒的粒径增加。实验发现,Co掺杂α-Fe_2O_3制成的电极在标准光照射下的最大光生电流密度为0.453 m A/cm2,是未掺杂样品的20.6倍,P掺杂α-Fe_2O_3制成的电极在标准光照射下的最大光生电流密度为0.276 m A/cm2,是未掺杂样品的12.5倍,具备了高效光解水性能。同时通过SEM、TEM、XRD、UV-Vis和Mott-Schottky测试等方法,结合形貌与结构表征,研究了α-Fe_2O_3的光电化学分解水性能影响机理。展开更多
采用一步滴涂法在掺氟二氧化锡(FTO)导电玻璃上制备了Bi_(1-x)Fe_(x)VO_4(x=0,0.05,0.10,0.25,0.40)薄膜,表征了其结构、形貌、光学以及光电化学方面的性质.结果表明,掺入Fe后Bi_(1-x)Fe_(x)VO_(4)薄膜的光电流密度与BiVO_(4)薄膜相比...采用一步滴涂法在掺氟二氧化锡(FTO)导电玻璃上制备了Bi_(1-x)Fe_(x)VO_4(x=0,0.05,0.10,0.25,0.40)薄膜,表征了其结构、形貌、光学以及光电化学方面的性质.结果表明,掺入Fe后Bi_(1-x)Fe_(x)VO_(4)薄膜的光电流密度与BiVO_(4)薄膜相比均有所提高,其中25%Fe-BiVO_(4)薄膜表现出最优的光电化学性能.在0.1 mol/L磷酸缓冲溶液(pH=7.0)中,1.23 V(vs.RHE)电势下25%Fe-BiVO_(4)薄膜的光电流密度为0.50 m A/cm~2,与BiVO_(4)薄膜的0.15m A/cm^(2)相比提高了3倍多.结合X射线衍射(XRD)、拉曼光谱(Raman)和X射线光电子能谱(XPS)表征结果证实Fe~(3+)以FeVO_(4)的形式存在于Bi_(1-x)Fe_(x)VO_(4)薄膜中,形成了BiVO_(4)/FeVO_(4)复合物薄膜.紫外-可见光谱(UV-Vis)结果显示,所有Bi_(1-x)Fe_(x)VO_4薄膜的禁带宽度均为2.4~2.5 e V.25%Fe-BiVO_(4)薄膜光电化学性能的提升主要归因于光生载流子转移效率(η_(trans))和分离效率(η_(sep))的提高.能级结构图表明,BiVO_(4)和FeVO_(4)之间可以形成TypeⅡ型能级结构排列,可以促进光生载流子的分离与转移,是25%Fe-BiVO_(4)薄膜光电化学性能提升的内在机理.展开更多
以钨粉(W)和双氧水(H2O2)为原料,通过液相合成法制备前驱体粉末后,采用刮刀涂布工艺制备了具有高光电化学(PEC)水氧化效率的WO3光阳极。并利用X射线衍射、拉曼光谱分析并结合热分析法研究煅烧温度对纳米WO3的晶型和晶粒直径的影响。结...以钨粉(W)和双氧水(H2O2)为原料,通过液相合成法制备前驱体粉末后,采用刮刀涂布工艺制备了具有高光电化学(PEC)水氧化效率的WO3光阳极。并利用X射线衍射、拉曼光谱分析并结合热分析法研究煅烧温度对纳米WO3的晶型和晶粒直径的影响。结果表明,煅烧温度为400℃时可制备单斜相WO3,且WO3的晶粒直径随温度升高而增大。扫描电镜分析结果表明,制备的WO3颗粒尺寸约为20~70 nm。环伏安测试结果表明,WO3-600光阳极的光电流达到1.88 m A/cm2,是WO3-400的2.65倍。入射光子-电流转换效率(IPCE)说明WO3光阳极的起始波长为470 nm。Co2+的添加大幅提升了PEC分解水的催化活性和稳定性。展开更多
Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as ...Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as a model photocathode in this study,and the photogenerated surface charge density,interfacial charge transfer rate constant and their relation to the water reduction rate(in terms of photocurrent)were investigated by a combination of(photo)electrochemical techniques.The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density,and that the photocurrent equals to the product of the charge transfer rate constant and surface charge density.The reaction is first-order in terms of surface charge density.Such an unconventional rate law contrasts with the reports in literature.The charge density-dependent rate constant results from the Fermi level pinning(i.e.,Galvani potential is the main driving force for the reaction)due to accumulation of charge in the surface states and/or Frumkin behavior(i.e.,chemical potential is the main driving force).This study,therefore,may be helpful for further investigation on the mechanism of hydrogen evolution over a CuO photocathode and for designing more efficient CuO-based photocatalysts.展开更多
文摘光电化学水分解电池能够将太阳能直接转化为氢能,是一种理想的太阳能利用方式.p-n叠层电池具有理论转换效率高、成本低廉、材料选择灵活等优势,被认为是最具潜力的一类光电化学水分解电池.然而,目前这类叠层电池的太阳能转化效率还不高,主要原因是单个电极的效率太低.本文介绍了几种提高光电极分解水性能的方法—减小光生载流子的体相复合、表面复合以及抑制背反应等,同时综述了国内外关于几种p型半导体光阴极的研究进展,如Si、In P、Cu In1-xGaxS(Se)2、Cu2Zn Sn S4等.通过总结,作者提出一种p-Cu2Zn Sn S4(Cu In1-xGaxS(Se)2)/n-Ta3N5(Fe2O3)组装方式,有望获得高效低成本叠层光电化学水分解电池.
文摘在众多光阳极材料中,纳米结构材料α-Fe_2O_3由于其光吸收显著、化学稳定性好、储量丰富等优势,被认为是最有前途的材料之一。利用水热法制备了具有良好光解水性能的Co和P掺杂α-Fe_2O_3纳米材料。经过掺杂后α-Fe_2O_3纳米材料仍为纳米棒状形貌,纳米棒的粒径增加。实验发现,Co掺杂α-Fe_2O_3制成的电极在标准光照射下的最大光生电流密度为0.453 m A/cm2,是未掺杂样品的20.6倍,P掺杂α-Fe_2O_3制成的电极在标准光照射下的最大光生电流密度为0.276 m A/cm2,是未掺杂样品的12.5倍,具备了高效光解水性能。同时通过SEM、TEM、XRD、UV-Vis和Mott-Schottky测试等方法,结合形貌与结构表征,研究了α-Fe_2O_3的光电化学分解水性能影响机理。
文摘采用一步滴涂法在掺氟二氧化锡(FTO)导电玻璃上制备了Bi_(1-x)Fe_(x)VO_4(x=0,0.05,0.10,0.25,0.40)薄膜,表征了其结构、形貌、光学以及光电化学方面的性质.结果表明,掺入Fe后Bi_(1-x)Fe_(x)VO_(4)薄膜的光电流密度与BiVO_(4)薄膜相比均有所提高,其中25%Fe-BiVO_(4)薄膜表现出最优的光电化学性能.在0.1 mol/L磷酸缓冲溶液(pH=7.0)中,1.23 V(vs.RHE)电势下25%Fe-BiVO_(4)薄膜的光电流密度为0.50 m A/cm~2,与BiVO_(4)薄膜的0.15m A/cm^(2)相比提高了3倍多.结合X射线衍射(XRD)、拉曼光谱(Raman)和X射线光电子能谱(XPS)表征结果证实Fe~(3+)以FeVO_(4)的形式存在于Bi_(1-x)Fe_(x)VO_(4)薄膜中,形成了BiVO_(4)/FeVO_(4)复合物薄膜.紫外-可见光谱(UV-Vis)结果显示,所有Bi_(1-x)Fe_(x)VO_4薄膜的禁带宽度均为2.4~2.5 e V.25%Fe-BiVO_(4)薄膜光电化学性能的提升主要归因于光生载流子转移效率(η_(trans))和分离效率(η_(sep))的提高.能级结构图表明,BiVO_(4)和FeVO_(4)之间可以形成TypeⅡ型能级结构排列,可以促进光生载流子的分离与转移,是25%Fe-BiVO_(4)薄膜光电化学性能提升的内在机理.
文摘以钨粉(W)和双氧水(H2O2)为原料,通过液相合成法制备前驱体粉末后,采用刮刀涂布工艺制备了具有高光电化学(PEC)水氧化效率的WO3光阳极。并利用X射线衍射、拉曼光谱分析并结合热分析法研究煅烧温度对纳米WO3的晶型和晶粒直径的影响。结果表明,煅烧温度为400℃时可制备单斜相WO3,且WO3的晶粒直径随温度升高而增大。扫描电镜分析结果表明,制备的WO3颗粒尺寸约为20~70 nm。环伏安测试结果表明,WO3-600光阳极的光电流达到1.88 m A/cm2,是WO3-400的2.65倍。入射光子-电流转换效率(IPCE)说明WO3光阳极的起始波长为470 nm。Co2+的添加大幅提升了PEC分解水的催化活性和稳定性。
基金the National Basic Research Development of China(2011CB936003)the National Natural Science Foundation of China(50971116)。
文摘Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as a model photocathode in this study,and the photogenerated surface charge density,interfacial charge transfer rate constant and their relation to the water reduction rate(in terms of photocurrent)were investigated by a combination of(photo)electrochemical techniques.The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density,and that the photocurrent equals to the product of the charge transfer rate constant and surface charge density.The reaction is first-order in terms of surface charge density.Such an unconventional rate law contrasts with the reports in literature.The charge density-dependent rate constant results from the Fermi level pinning(i.e.,Galvani potential is the main driving force for the reaction)due to accumulation of charge in the surface states and/or Frumkin behavior(i.e.,chemical potential is the main driving force).This study,therefore,may be helpful for further investigation on the mechanism of hydrogen evolution over a CuO photocathode and for designing more efficient CuO-based photocatalysts.
