Highly Active Sb2S3-Attached Mo-WO3 Composite Film for Enhanced Photoelectrocatalytic Water Splitting at Extremely Low Input Light Energy

We prepared platelike Mo-doped WO3 films (Mo-WO3) deposited with Sb2S3 for photoelectrocatalytic (PEC) water splitting under visible-light illumination at extremely low input energy (1 mW cm(-2)). The 5% Mo-WO3 film exhibited optimal PEC water-splitting performance. Furthermore, Sb2S3/5% Mo-WO3 composite film achieved the highest photocurrent density of 0.42 mA cm(-2), nearly 20 times as high as that of 5% Mo-WO3 film. The outstanding PEC water-splitting performance was mainly attributed to synergistic effects of Mo doping and deposited Sb2S3; that is, the enhanced PEC performance not only was assigned to the broadened optical spectrum but also improved electron-hole pairs separation and transfer efficiency. Density functional theory calculation revealed that Mo dopant can modulate the intrinsic electronic structure of WO3 and introduce impurity energy levels resulting from the hybridization between M 3d and O 2p states around the Fermi level, resulting in improved electrical conductivity. Therefore, this work offers new insight for designing metal elements doping into WO3 associated with multifunctional electrode materials for high PEC visible-light-induced water-splitting activity in neutral electrolyte.