Yong Li,Yanfang Liu,Mingqing Zhang,Qianyu Zhou,Xin Li,Tianlu Chen,Shifeng Wang
Photocatalytic degradation, as an emerging method to control environmental pollution, is considered one of the most promising environmental purification technologies. As Tibet is a region with some of the strongest solar radiation in China and even in the world, it is extremely rich in solar energy resources, which is ideal for applying photocatalytic technology to its ecological environment protection and governance. In this study, Na2Ti3O7nanobelts were prepared via a hydrothermal method and converted to TiO2∙xH2O ion exchange, which was followed by high-temperature calcination to prepare TiO2(B) nanobelts (“B” in TiO2(B) means “Bronze phase”). A simple in situ method was used to generate Ag3PO4particles on the surface of the TiO2nanobelts to construct a Ag3PO4/TiO2(B) heterojunction composite photocatalyst. By generating Ag3PO4nanoparticles on the surface of the TiO2(B) nanobelts to construct heterojunctions, the light absorption range of the photocatalyst was successfully extended from UV (ultraviolet) to the visible region. Furthermore, the recombination of photogenerated electron–hole pairs in the catalyst was inhibited by the construction of the heterojunctions, thus greatly enhancing its light quantum efficiency. Therefore, the prepared Ag3PO4/TiO2(B) heterojunction composite photocatalyst greatly outperformed the TiO2(B) nanobelt in terms of photocatalytic degradation.Keywords:photocatalyst;heterojunction;photocatalytic degradation;TiO2(B) nanobelts
Herein, we report the high performance of thermally reduced Pt/TiO2(B) catalysts for the catalytic oxidation of CO. Our findings show that through hydrogen spillover from Pt to TiO2, surface-engineered defects of oxygen vacancies are “constructed” on the TiO2 support during the reduction process, thus generating active surface-adsorbed oxygen species. With an increase of the reduction temperature, the TiO2(B) phase gradually transforms to the anatase phase, which takes place from the bulk to the surface of TiO2, and is eventually completed at 700 °C. Compared with the anatase phase, the oxygen vacancies are more easily formed on the TiO2(B) phase, and the latter has much stronger interactions with Pt, as well. As the reduction temperature increases, the metal–support interaction between Pt and TiO2(B) is strengthened. Meanwhile, we simultaneously observe an increase in the dispersion of Pt, the proportion of Pt0 and the adsorbed oxygen species on the surface. Our findings reveal that for thermally reduced Pt/TiO2 catalysts, surface-adsorbed oxygen and Pt0 are active species for the catalytic oxidation of CO. Among the thermally reduced catalysts, H-600 shows the highest catalytic activity because it has the largest amount of active Pt0 sites and surface-adsorbed oxygen species. In addition, it shows high water vapor resistance.
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