Study on the mechanisms of photoinduced carriers separation and recombination for Fe3+–TiO2 photocatalysts

• DOI: 10.1016/j.apsusc.2006.09.049
• Publication Date: 2006-10-26T11:25:15Z
• Authors: Baifu Xin; Zhiyu Ren; Peng Wang; Jia Liu; Liqiang Jing; Honggang Fu
• Keywords: Surface Photovoltage; Photoinduced electron transfer; Photoinduced charge separation

Abstract The iron(III)-ion doped TiO 2 (Fe 3+ –TiO 2 ) with different doping Fe 3+ content were prepared via a sol–gel method. The as-prepared Fe 3+ –TiO 2 nanoparticles were investigated by means of surface photovoltage spectroscopy (SPS), field-induced surface photovoltage spectroscopy (FISPS), and the photoelectrochemical properties of Fe 3+ –TiO 2 catalysts with different Fe 3+ content are performed by electrical impedance spectroscopy (EIS) as well as photocatalytic degradation of RhB are studied under illuminating. Based on the experiment results, the mechanism of photoinduced carriers separation and recombination of Fe 3+ –TiO 2 was revealed: that is, the Fe 3+ captures the photoinduced electrons, inhibiting the recombination of photoinduced electron–hole pairs, this favors to the photocatalytic reaction at low doping concentration (Fe/Ti ≤ 0.03 mol%); while Fe 3+ dopant content exceeds 0.03 mol%, Fe 2 O 3 became the recombination centers of photoinduced electrons and holes because of that the interaction of Fe 2 O 3 with TiO 2 leads to that the photoinduced electrons and holes of TiO 2 transfer to Fe 2 O 3 and recombine quickly, which is unfavorable to the photocatalytic reaction.