Spatial Specific Janus S-Scheme Photocatalyst with Enhanced H2 O2 Production Performance.

Photocatalytic oxygen reduction reaction (ORR) for H2 O2 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 H2 O2 decomposition to a large extent. The TiO2 @RF photocatalyst shows a high H2 O2 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 H2 O2 production.