A novel S-scheme heterojunction photocatalyst, Yb

The increasing reliance on fossil fuels has led to a surge in atmospheric CO₂, intensifying global warming, whereas water contamination by organic pollutants presents another pressing global issue. In response, we have developed Yb₆Te₅O₁₉.₂/g-C₃N₄ (YTO/GCN) composites as novel S-scheme photocatalysts that efficiently target the degradation of pollutants and CO₂ reduction. These composites were synthesized through a straightforward hydrothermal method and comprehensively characterized via XRD, SEM, TEM‒EDS, DRS, BET, PL, and XPS analyses. Compared with the individual YTO and GCN semiconductors, the YTO/GCN heterojunction demonstrated superior photocatalytic efficiency in both crystal violet (CV) degradation under visible-light irradiation and CO₂ photoreduction. The YTO-90%GCN composite achieved the highest CV degradation rate constant (0.043 h⁻¹), which surpassed those of YTO and GCN by 2.97 and 1.11 times, respectively. Furthermore, the YTO-90%GCN composite produced 0.449 µmol/g CH₄ from CO₂ reduction over 216 h, which was 1.07 and 9.78 times greater than that of YTO and GCN alone, respectively. Scavenger and ESR experiments were conducted to identify the active species involved in CV degradation and to elucidate the photocatalytic mechanism of the YTO/GCN composite.