Efficient Visible-Light-driven Hydrogen Evolution over Ternary MoS2/Pt-TiO2 Photocatalysts with Low Overpotential

By surface-decorating Pt-TiO2 hybrid catalyst with MoS2 nanosheets, we prepared a new MoS2/Pt-TiO2 ternary system as high-performance photocatalysts. The ternary MoS2/Pt-TiO2 outperforms both the binary MoS2-TiO2 and Pt-TiO2 systems in photocatalytic hydrogen evolution with an AQY (apparent quantum yield) value of 12.54% at 420 nm, owing to the unique ternary design that creates more efficient electron transport path and electron-hole separation mechanism. Electrochemical characterization showed that the MoS 2 /Pt-TiO2 ternary electrode afford an efficient pathway of photo-excited electrons from TiO2 to surface-decorated Pt nanoparticles using MoS2 and internal Pt nanoparticles as bridges, thus significantly promoting electron transfer, reducing the system over-potential and leading to the activation of more reactive sites. This internal electron transfer pathway (TiO2 -> Pt (internal) MoS2 -> Pt (surface)) eliminates the need of other metal cocatalysts because the Pt nanoparticles play two roles of storing the conduction band electrons of TiO2 and acting as co-catalyst for reduction of protons to hydrogen. This unique ternary metal-semiconductor heterojunction for efficient photocatalytic hydrogen evolution provides a meaningful reference for reasonable design of other hybrid photocatalysts. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.