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 H2 and O2 evolution. In this study, RP was decorated by trace amount of WO3 to greatly enhance the photocarriers separation and photocatalytic activity for overall water splitting under visible light. The 2.5% WO3/RP composite achieved the highest activity to produce H2 and O2, and the activity was 7.0 times that of pure RP under visible light (lambda >= 420 nm). The significantly increased photocarriers separation of WO3/RP was ensured by transient photocurrent, electrochemical impendence, photoluminescence, and time-resolved photoluminescence characterizations. More importantly, WO3/RP maintained high stability when it was persistently used for 20 cycles. Based on the reactive oxygen species (center dot O-2(-) and center dot OH) detected during the photocatalytic process, an S-scheme mechanism was proposed for WO3/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.

Automated summary

Decorating red phosphorus with trace amount of WO3 greatly enhances photocarriers separation and overall water splitting catalytic activity. The proposed S-scheme mechanism efficiently separates photocarriers for improved water splitting activity of red phosphorus.