Enhanced photocatalytic hydrogen evolution over Pt supported on mesoporous TiO_2 prepared by single-step sol-gel process with surfactant template

摘要

Nanocrystalline mesoporous TiO_2 photocatalyst with narrow pore size distribution was synthesized by a surfactant-assisted templating sol-gel technique and used as a support for Pt towards photocatalytic H_2 evolution. Single-step sol-gel (SSSG) method, in which Pt precursor was introduced into the completely hydrolyzed TiO_2 sol prepared with a mesopore-directing surfactant template, was utilized to load the Pt cocatalyst onto the synthesized mesoporous TiO_2. In comparison, the conventional loading methods namely incipient wetness impregnation (IWI) and photochemical deposition (PCD) were also performed. The mesoporous Pt/TiO_2 photocatalyst prepared by the SSSG method showed higher photocatalytic activity for H_2 evolution over entire range of Pt loading content (optimum loading of 0.6 wt%) as well as broader photocatalytic activity window with respect to the amount of loaded Pt than those prepared by the other two methods and Pt/Degussa P-25 TiO_2. Hence, the SSSG method has been postulated as a beneficial alternative for synthesis of effective metal-loaded mesoporous photocatalyst.