Construction of spherical WO3/CdS S-scheme heterojunction for photocatalytic H2O2 production in real seawater

s Photocatalytic H 2 O 2 production represents a sustainable and promising avenue for energy and environment. Photoproduction of H 2 O 2 in seawater is potentially an alternative to meet the needs of H 2 O 2 utilization in ocean, while with challenges of competitive ions influence and unsolved photocatalytic mechanism. Herein, we constructed a S-scheme heterojunction with the lamellated WO 3 coated CdS semiconductors for photoproduction of H 2 O 2 in actual seawater. Fragmented WO 3 uniformly spread on surface of dispersed CdS spheres by two steps including calcination and ultrasound. Photocatalyst achieved considerable 1.00 mmol·g cat −1 ·h −1 of H 2 O 2 productivity in seawater without electron-proton donors and pure O 2 , 9.3 % of apparent quantum yield (AQY), as well as good reusability. A co-catalysis concept was proposed to explore specific role of ions in seawater on H 2 O 2 photoproduction. S-scheme heterojunction contributed to migration of electrons and holes on interface between WO 3 and CdS, and further promoted separation of photocarriers, and further opened another channel for H 2 O 2 generation. Accumulated electrons in conduction band (CB) of CdS involved in the main route of two-electron reduction of O 2 for H 2 O 2 production, also promoted generation of •O 2 - for opening the auxiliary route. WO 3 /CdS heterojunction provided fundamentals and opportunities for H 2 O 2 production and applications in abundant seawater as a sustainable way.