Decoration of size-tunable CuO nanodots on TiO2 nanocrystals for noble metal-free photocatalytic H2 production

Abstract

We report a simple yet effective approach for the decoration of the TiO₂ nanocrystal surface with size-tunable CuO nanodots for high-performance noble metal-free photocatalytic H₂ production. Modification with polyacrylic acid enables the surface of TiO₂ nanocrystals to be selectively deposited with Cu(OH)₂ nanodots, which can be subsequently converted to CuO through dehydration without changing their morphologies. UV irradiation of the nanocomposite solution in the presence of a hole scavenger produces photogenerated electrons which reduce CuO to metallic Cu nanodots, making them effective co-catalysts in a role similar to Pt for promoting photocatalytic H₂ production. Due to the considerably high work function of Cu, the formation of a metal–semiconductor Schottky junction induces efficient charge separation and transfer. As a result, the TiO₂ nanocrystals decorated with an optimal amount of CuO nanodots (1.7 wt%) could reach ∼50% of the photocatalytic activity achievable by the Pt–TiO₂ counterparts (1 wt%), clearly demonstrating the great potential of such composite catalysts for efficient noble metal-free photocatalytic H₂ production.