Enhancement of catalytic activity of AgPd@Pd/TiO2 nanoparticles under UV and visible photoirradiation

Abstract

The effects of photoirradiation for the production of hydrogen from the decomposition of formic acid (FA) were studied using Ag₉₃Pd₇@Pd/TiO₂ (anatase (A) or P25 (P)) nanocatalysts. The catalytic activity was enhanced by a factor of 1.5–1.6 under UV and visible (vis) photoirradiation at room temperature for both TiO₂ supports. It was explained by the formation of an electron-rich Pd shell because of the migration of photogenerated electrons from the TiO₂ surface. The catalytic activity of Ag₉₃Pd₇@Pd/TiO₂ (A) was 1.7–7.3 times higher than that of Ag₉₃Pd₇@Pd/TiO₂ (P) without and under photoirradiation at 27–90 °C. The catalytic activity of Ag₉₃Pd₇@Pd/TiO₂ (A) under photoirradiation at 27 °C with 468 mmol H₂ g per catalyst per h, is the best value ever reported out of all of the heterogeneous catalysts using TiO₂ (A) as a photocatalyst at room temperature.