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The dependence of photocatalytic activity on the selective and nonselective deposition of noble metal cocatalysts on the facets of rutile TiO2

Zhang, Qiao, Li, Rengui, Li, Zheng, Li, Ailong, Wang, Shengyang, Liang, Zhenxing, Liao, Shijun, Li, Can
Journal of catalysis 2016 v.337 pp. 36-44
electrons, fluorides, hydrogen production, metals, models, photocatalysis, semiconductors, titanium dioxide
The spatial loading of redox cocatalysts on the different facets of a semiconductor is a novel and ideal approach to constructing an efficient photocatalytic system. Here, taking the series of rutile TiO2 as the research model, the origin of the preferential deposition of noble metal cocatalysts on the particular facet (110) was carefully studied under various experimental conditions, including the effect of fluoride species on the surface, as well as different noble metal deposition methods. Our results clearly show that the noble metals could be photodeposited exclusively on the (110) facet. This implies that the origin of noble metal preferential deposition on the (110) facet of rutile TiO2 is due to the reduction of the noble metal precursors by the photoexcited electrons enriched on the particular facet of (110). Rutile TiO2 samples with cocatalyst selectively deposited on the (110) facets have much higher photocatalytic H2 production activity than rutile samples with noble metal cocatalysts randomly deposited on the entire surface. This demonstrates that facet charge separation upon photoexcitation may be a unique route for efficient photocatalytic systems.