关键词: 超微粒, 氧化铁, 光电流, 拉曼光谱, 紫外－可见反射谱

Abstract: 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.