Spatial Specific Janus S-Scheme Photocatalyst with Enhanced H₂O₂ Production Performance

Photocatalytic oxygen reduction reaction (ORR) for H₂O₂ production in the absence of sacrificing agents is a green approach and of great significance, where the design of photocatalysts with high performance is the central task. Herein, a spatial specific S-scheme heterojunction design by introducing a novel semiconducting pair with a S-scheme mechanism in a purpose-designed Janus core–shell-structured hollow morphology is reported. In this design, TiO₂ nanocrystals are grown inside the inner wall of resorcinol-formaldehyde (RF) resin hollow nanocakes with a reverse bumpy ball morphology (TiO₂@RF). The S-scheme heterojunction preserves the high redox ability of the TiO₂ and RF pair, the spatial specific Janus design enhances the charge separation, promotes active site exposure, and reduces the H₂O₂ decomposition to a large extent. The TiO₂@RF photocatalyst shows a high H₂O₂ yield of 66.6 mM g⁻¹ h⁻¹ and solar-to-chemical conversion efficiency of 1.11%, superior to another Janus structure (RF@TiO₂) with the same heterojunction but a reversed Janus spatial arrangement, and most reported photocatalysts under similar reaction conditions. The work has paved the way toward the design of next-generation photocatalysts for green synthesis of H₂O₂ production.