Photocatalytic degradation of organic pollutants under visible light has attracted interest for wastewater treatment due to its effective use of solar light radiation. In this study, a series of ZnTi MMO (ZTM) photocatalysts was synthesized by varying the molar ratio of Zn2+/Ti4+ with different calcination temperatures of layered double hydroxides (LDHs) as an intermediate precursor. The optical, electronic, interfacial and microstructure properties of ZTM photocatalysts were characterized by diverse analytical techniques such as scanning electron microscopy, powder X-ray diffraction (PXRD), surface area and diffused reflectance UV-visible spectroscopy. Moreover, an important surface electronic properties of ZTM was investigated in energy-resolved distribution of electron traps (ERDT) by reversed double-beam photoacoustic spectroscopy. From ERDT results, different molar ratio of Zn2+/Ti4+ of ZTM photocatalyst showed similar ERDT pattern, implying that these samples might be in the same phase components of ZnO, and (amorphous) ZnTiO3 which cannot be distinguished by PXRD. The different molar ratios of Zn2+/Ti4+ photocatalysts (calcined at 500°C) have similar ERDT patterns and similar phenol photocatalytic activities. In addition, the similar ERDT patterns have a high electron accumulation level near conduction band bottom (CBB) which are close to one-electron transfer of superoxide radical production. However, the ZTM (calcined at 600°C) showed low photocatalytic efficiency with different ERDT patterns due to Zn2TiO4 phase and low electron accumulation near CBB. The greater photocatalytic performance of the ZTM samples could be attributed to improve light absorption ability and avoid the recombination of photogenerated charge carriers.

Energy-resolved distribution of electron traps study for ZnTi mixed metal oxides as photocatalysts to degrade phenol

2019 Fall National Meeting

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