Optimizing Electronic Density at Active W Sites for Boosting Photocatalytic H<sub>2</sub> Evolution
Jing Xu, Xueqi Zhang, Wei Yan, Tengfeng Xie, Yuanping Chen, Yingcong Wei
Abstract
It is highly desirable but challenging to optimize the electronic structure of an active site to realize moderate active site-H ads bond energies for boosting photocatalytic H 2 evolution. Herein, an interfacial engineering strategy is developed to simultaneously concentrate hydrogen species and accelerate the combination of an H ads intermediate to generate free H 2 by constructing W–WC–W 2 C (WCC) cocatalysts. Systematic investigations reveal that hybridizing with W 2 C creates electron-rich W active sites and effectively induces the downshift of the d-band center of W in WC. Consequently, the strong W–H ads bonds on the surface of WC are weakened, thus promoting the desorption of H ads to rapidly produce free H 2 . The optimized 40-WCC/CdS photocatalyst exhibits a high hydrogen evolution rate of 63.6 mmol g –1 h –1 under visible light (≥420 nm) with an apparent quantum efficiency of 39.5% at 425 nm monochromatic light, which is about 40-fold of the pristine CdS. This work offers insights into the design of cocatalyst for high-efficiency photocatalytic H 2 production.