Rational construction of Ag₃PO₄/WO₃ step-scheme heterojunction for enhanced solar-driven photocatalytic performance of O₂ evolution and pollutant degradation

Heterojunction engineering has been regarded as a promising strategy to sufficiently utilizing photogenerated charge carriers, thus benefiting the improvement of photocatalytic performance. Herein, Ag₃PO₄/WO₃ S-scheme heterojunction was synthesized via a simple deposition-precipitation process, and its photocatalytic activity was evaluated by monitoring water splitting and pollutant degradation under visible light. As a result, Ag₃PO₄/WO₃ with optimized ratio photocatalyst showed enhanced photocatalytic activity in oxygen production (306.6 μmol·L^-1·h^-1) relative to pure Ag₃PO₄ (204.4 μmol·L^-1·h^-1). Additionally, it also exhibits rapid toxicity elimination efficiency over hexavalent chromium ions (Cr⁶⁺) and ciprofloxacin (CIP) with degrading rate of 72% and 83% within 30 min, respectively. According to a series characterization, a possible S-scheme photocatalytic mechanism of Ag₃PO₄/WO₃ was demonstrated in detail, which endowed the heterojunction with strong redox abilities to provide powerful diving force towards the photocatalytic reaction. This work presents an innovative perspective to construct Ag₃PO₄-based S-scheme heterojunctions for boosting photocatalytic performance for various applications.