Roles of photo-generated holes and oxygen vacancies in enhancing photocatalytic performance over CeO2 prepared by molten salt method |
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Affiliation: | 1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;2. Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing 400044, China |
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Abstract: | A series of CeO2 photocatalysts were synthesized through the molten salt method. The photocatalytic activity was evaluated through the degradation of methyl orange (MO). Systematic characterizations including X-ray diffraction, Scanning electron microscopy, Fourier transformed infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, electron spin-resonance spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence spectrometry, photocurrent response and electrochemical impedance spectroscopy were conducted to study the as-prepared CeO2 samples. It was found that, under ultraviolet light irradiation, the apparent rate constants of CeO2 prepared at 800 °C for degradation of MO was about 3.4 times higher than CeO2 prepared at 500 °C. CeO2 prepared at 800 °C held the higher oxygen vacancies concentration. According to the trapping experiments, it was demonstrated that photo-generated holes played a dominant role in this photocatalytic system. Furthermore, the possible photocatalytic mechanism which showed the roles of photo-generated holes and oxygen vacancies was proposed. |
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Keywords: | Photo-generated holes Oxygen vacancies Photocatalytic mechanism |
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