Novel S-scheme WO3/RP composite with outstanding overall water splitting activity for H2 and O2 evolution under visible light

Elemental red phosphorus (RP) has an ultra-low activity of splitting water for H 2 and O 2 evolution. In this study, RP was decorated by trace amount of WO 3 to greatly enhance the photocarriers separation and photocatalytic activity for overall water splitting under visible light. The 2.5% WO 3 /RP composite achieved the highest activity to produce H 2 and O 2 , and the activity was 7.0 times that of pure RP under visible light (λ ≥ 420 nm). The significantly increased photocarriers separation of WO 3 /RP was ensured by transient photocurrent, electrochemical impendence, photoluminescence, and time-resolved photoluminescence characterizations. More importantly, WO 3 /RP maintained high stability when it was persistently used for 20 cycles. Based on the reactive oxygen species ( O 2 − and OH) detected during the photocatalytic process, an S-scheme mechanism was proposed for WO 3 /RP composites to efficiently separate the photocarriers. This work provides a notion for improving the overall water splitting activity of RP via an S-scheme photocarriers separation mode.