Experimental and theoretical investigation of the enhancement of the photo-oxidation of Hg0 by CeO2-modified morphology-controlled anatase TiO2

This study aims to investigate the coeffects of predominantly exposed anatase TiO2{001} and {101} and CeO2 loading on the photo-oxidation of Hg0 to relieve the adverse effects caused by higher temperatures of 50–250 °C. The effect of loading CeO2 on the photocatalytic activity of morphology-controlled TiO2 was not only investigated using DFT with U correction but also experimentally analyzed by characterizing the electrochemical properties and the formation of free radicals. The theoretical calculation showed that CeO2 loading on TiO2{101} was more stable than that on TiO2{001}. Accordingly, a larger portion of CeO2 was observed to anchor to the (101) plane than to the (001) plane. CeO2 loading is more beneficial for increasing the distribution of photo-induced electrons and holes on the surface of 7%CeTi than on the surface of TiO2 and increases the energy difference between the conduction band edge of 7%CeTi and the standard redox potential of O2/·O2−. Correspondingly, the photocatalytic removal efficiencies (PREs) of Hg0 by 7%CeTi were significantly enhanced compared with those of pristine TiO2. The effect of CeO2 was highly morphologically dependent on the photocatalytic activity. This study provides valuable insight into surface engineering strategies for morphology-controlled photocatalysts for air pollution control technology.