화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.160, 722-729, 2014
Dominated factors for high performance of Fe3+ grafted metal doped TiO2 based photocatalysts
We examined dominated factors for visible light driven performance of the Fe3+ grafted metal doped TiO2 based photocatalyst (Fe/Me:TiO2) by means of ESR spectroscopy and active oxygen detection. For the performance of the Fe/Me:TiO2, in addition to a direct electron transfer from TiO2 valence band to the grafted Fe3+, indirect electron transfers to the Fe3+ are important. In this work, it was revealed that the electron acceptor state formed close to the redox potential of the grafted Fe3+ to Fe2+ by doping metal ions leaded to enhancement of the photocatalytic activity because the efficiency of the indirect electron transfer via acceptor level to the Fe3+ was high. The other indirect electron transfer via metal ions of donor state to the Fe3+ did not lead to large enhancement of photocatalytic activity. A two-step electron excitation from TiO2 valence band to conduction band via defect level under visible light irradiation was a path with high recombination rate of electron-hole and therefore could not contribute to the photocatalytic activity. Moreover the defect level decreased the efficiency of the direct electron transfer from the TiO2 valence band to the Fe3+, resulting in decrease of photocatalytic activity. (C) 2014 Published by Elsevier B.V.