only a Japanese version



2017年5月16日(火)15:10 理学研究科Z402講義室

Towards Visible Light Active Bi2O3 for Environmental Photocatalysis

Dr. Hanggara Sudrajat
Department of Material Science, Chulalongkorn University, Thailand

Among metal oxides, Bi2O3 is shown to be a promising candidate for visible light photocatalysis due to its narrow band gap of 2.6 eV and deep valence band edge top of +2.9 V vs NHE. Unfortunately, its conduction band edge bottom (+0.33 V vs NHE) is more positive than the potential for the single-electron reduction of O2 (O2 + e- = O2- radical, E = -0.06 V vs NHE). Therefore, the photogenerated electrons cannot be consumed by the adsorbed O2 to produce O2- radicals, and in turn recombine with holes. To address such a critical issue, various strategies for photocatalytic activity improvement are employed through morphology tuning, metal grafting, metal and nonmetal doping, and heterostructuring with graphene, reduced graphene oxide and graphitic carbon nitride. Structural elucidation is performed using a variety of state of the art techniques including synchrotron-based techniques such as UPS, XANES, EXAFS and SXAS. Appreciable improvements of photocatalytic activity are shown for degradation and mineralization of recalcitrant organic compounds under visible light. The degradation pathways of those organic compounds are deeply investigated, and the toxicity of the photocatalytically treated effluent is also comprehensively assessed by different bioassays.