Core-shell Ag@Ni cocatalyst on the TiO2 photocatalyst: One-step photoinduced deposition and its improved H-2-evolution activity

Compared with well-known Pt, metallic Ag usually shows a far low H-2-evolution rate due to its serious capacitive property and poor H-2-evolution activity for Ag-modified photocatalysts. Herein, low-cost metallic Ni cocatalyst is directionally assembled onto the Ag nanoparticle to generate core-shell Ag@Ni cocatalyst, with an aim of greatly boosting the hydrogen-generation performance of metallic Ag. In this case, the core-shell Ag@Ni cocatalyst can be easily loaded onto the TiO2 surface to prepare the core-shell Ag@Ni/TiO2 photocatalysts by a facile one-step photoinduced deposition method. Photocatalytic results manifeste that compared with Ag/TiO2, all the core-shell Ag@Ni/TiO2 samples display a markedly enhanced photocatalytic hydrogen-production rate. Especially, the Ag@Ni/TiO2(1.5:1.5) sample exhibits the highest hydrogen-generation rate (2933.9 mu mol h(-1) g(-1), AQE = 12.12%) due to the synergistic effect of metallic Ag and Ni, namely, Ag core as electronic capturer to efficiently collect photoexcited electrons while Ni shell as interfacial active center to boost hydrogen-generation rate.