Improved Hydrogen Production of Au-Pt-CdS Hetero-Nanostructures by Efficient Plasmon-Induced Multipathway Electron Transfer

The design of new functional materials with excellent hydrogen production activity under visible-light irradiation has critical significance for solving the energy crisis. A well-controlled synthesis strategy is developed to prepare an Au-Pt-CdS hetero-nanostructure, in which each component of Au, Pt, and CdS has direct contact with the other two materials; Pt is on the tips and a CdS layer along the sides of an Au nanotriangle (NT), which exhibits excellent photocatalytic activity for hydrogen production under light irradiation (lambda > 420 nm). The sequential growth and surfactant-dependent deposition produce the three-component Au-Pt-CdS hybrids with the Au NT acting as core while Pt and CdS serve as a co-shell. Due to the presence of the Au NT cores, the Au-Pt-CdS nanostructures possess highly enhanced light-harvesting and strong local-electric-field enhancement. Moreover, the intimate and multiinterface contact generates multiple electron-transfer pathways (Au to CdS, CdS to Pt and Au to Pt) which guide photoexcited electrons to the co-catalyst Pt for an efficient hydrogen reduction reaction. By evaluating the hydrogen production rate when aqueous Na2SO3-Na2S solution is used as sacrificial agent, the Au-Pt-CdS hybrid exhibits excellent photocatalytic activity that is about 2.5 and 1.4 times larger than those of CdS/Pt and Au@CdS/Pt, respectively.