摘要
用拉曼光谱、光电流、紫外－可见反射谱等技术研究了附着在铂片表面的α－Ｆｅ＿２Ｏ＿３微粒．拉曼光谱的蓝移现象说明５０ｎｍ粒径的粒子较块体材料有尺寸量子化效应．随着电极电势的变化，光电流增加时，ＵＶ－ＶＩＳ反射率相对变化量减少；光电流减少，ＵＶ－ＶＩＳ反射率相对变化量则增大，说明电极电势不仅影响溶液氧化－还原对的氧化还原趋势，而且还影响微粒表面的光吸收．
in this paper, Raman spectra, photocurrent and the UV-VIS reflectance aremeasured for studying the α-Fe_2O_3ultrafine particles adsorbed on Pt electrode. The blue shifts ofRaman peaks demonstrate the size quantization effect for the particles of 50 nm in diameter ascompared with the bulk material. With the changing of the potential , the photocurrent decrcases as theUV-VIS reflectance increases, and vice-versa. Therefore, the potential not only affects the hargetransfer direcdtion in the interface of electrede/redox couple, but also influences the light absortion onthe surface of particles.According to the results of photoelectrochemistry, we suggest that the cathedicphotocurrent in the potential range of more than negative 270 mV arises from a reduction process ofthe photo-induced oxidation product on the platinum substrate electrixle and the anodic one in the rangeof more than positive 270 mV, and arises from a directly photo-induced oxidation process on thesurface of partiles.
出处
《电化学》
CAS
CSCD
1995年第2期146-151,共6页
Journal of Electrochemistry
基金
国家自然科学基金
国家教委优秀青年教师基金
关键词
超微粒
氧化铁
光电流
散射谱
光电转换机理
Ultrafine particle, lron oxide, Photocurrent,Raman spectre, UV-VISreflectance
