Self-built field induces surface electrons to reduce H⁺ to atomic H* for photocatalytic hydrodechlorination of 2-chlorophenols

2-chlorophenols (2-CPs) as a biodegradation-resistant pollutant has serious threats to environment and human health. Photocatalytic hydrodechlorination (PHDC) for removal of halogenated organics in water has attracted more attention, however, low utilization-efficiency of atomic H* limits its application. Here, a platinum-load tungsten phosphide/graphitic carbon nitride photocatalyst (Pt-WP/g-C₃N₄) with enhanced activity for conversion of 2-CPs to biodegradable phenol is designed via prior density-functional-theory (DFT) simulations. Conversion yield of phenol on Pt-WP/g-C₃N₄ is 92.0%, which is far higher than that of Pt-g-C₃N₄ (17.8%). Self-built field among Pt, WP and g-C₃N₄ induces photo-generated electrons migration to reduce H⁺, while g-C₃N₄ acts as a ‘H-atom lagoons’ to store H*. Electron spin-resonance spectroscopy indicates that coupling of WP and Pt-g-C₃N₄ promotes H* production and utilization. Ab-initio molecular-dynamics simulations show that Pt-W-P interface has a good resistance to deactivation to enhance H* generation. It provides a deep understanding of PHDC mechanism and a feasible way to optimize decontamination on heterojunction photocatalyst.