Cd Single Atom as an Electron Mediator in an S‐Scheme Heterojunction for Artificial Photosynthesis of H₂O₂

Abstract Developing conductor‐mediated S‐scheme heterojunction photocatalysts imitating natural photosynthetic systems emerges as a promising approach to hydrogen peroxide (H₂O₂) production. However, achieving precise coupling between two semiconductors with a charge shuttle and modulating the interfacial interactions still remain a significant bottleneck. Herein, we propose a catalyst architecture with a Cd single atom mediated S‐scheme heterojunction formed by interfacing CdS and TiO₂ nanoparticles. This catalyst exhibits an H₂O₂ production rate as high as 60.33 µmol g⁻¹ min⁻¹ under UV–vis light irradiation, which is attributed to the efficient charge transport at the interface of CdS and TiO₂ thanks to the Cd single atom mediated S‐scheme. In‐situ X‐ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) spin‐trapping tests confirm the S‐scheme charge transfer route. Femtosecond transient absorption (fs‐TA) spectroscopy and other ex‐situ characterizations further corroborate the efficient charge transport across the catalyst interface. This work offers a new perspective on constructing single atoms mediated heterojunctions to enhance photocatalytic performance.