Minireview Elaborating S-Scheme Charge Dynamic Photocatalysts: Journey from Z to S, Mechanism of Charge Flow, Characterization Proof, and H2O2 Evolution

In recent years, S-scheme oriented photocatalytic systems have shown tremendous potential and possibilities toward efficient conversion of solar energy to clear and sustainable chemical fuel owing to superior exciton separation and strong redox ability. This minireview summarizes the background history of the S-scheme mechanism along with a brief discussion of the type of band alignment and the journey from Z-scheme type to S-scheme systems. The review also elaborates the detailed operational mechanism and beneficial features of the S-scheme photocatalyst, including construction tactics, necessary conditions, band bending, and built-in electric field along with charge transfer dynamics. More importantly, we have described thoroughly the frequently used characterization techniques that demonstrate the interfacial charge transfer mechanism through S-scheme systems (XPS, in situ XPS, KPFM, and TRPL analysis) referring to the relevant reported literature with a brief computational interpretation. Additionally, the review highlights recent studies on the H2O2 evolution reaction with particular emphasis on S-scheme-oriented systems. The conclusion and future prospective section focuses on associated challenges and insightful newly reported information for the research community to fully understand the chemistry of S-scheme-based charge flow and design, promising systems for achieving benchmark efficiency in the clean energy generation sector.