Advanced engineering of an S-scheme BiCoO3/Co-g-C3N4 composite material supported on reduced graphene oxide for efficient photocatalytic activity

Abstract

Photo-assisted catalysis, distinguished by its mild reaction conditions, robust efficacy, and sustainable nature, is envisioned as a transformative solution for future environmental protection. Perovskites have garnered significant research attention and have been applied in the degradation of organic matter owing to their structural and catalytic efficacy. Moreover, bismuth-based perovskites exhibit exceptional crystal architectures coupled with extensive light-responsive ranges, facilitating the effective harnessing of solar energy. This study seeks to design an S-scheme-based heterostructure by integrating BiCoO₃ (BCO) with Co-g-C₃N₄ to markedly improve the photocatalytic efficacy and provide support for the reduced graphene oxide. UV-vis DRS results reveal the optimal band gap of BCO (1.90 eV), g-C₃N₄ (2.82 eV), and Co-g-C₃N₄ (2.68 eV) and show that the Co dopant modulates the bandgap of g-C₃N₄ and elevates its ability to absorb visible light. Subsequent photocatalytic evaluation demonstrated that the BCO/Co-g-C₃N₄/rGO heterostructure shows superior activity towards both safranin-O (99%) and methyl orange (97%). Radical scavenging tests provide evidence that ˙O₂⁻ and ˙OH are the key factors that are responsible for the dye degradation process. TOC measurements showcase the mineralization of the safranin-O (80%) and methyl orange dye (69%) by BCO/Co-g-C₃N₄/rGO in 90 minutes. The outstanding efficacy and stability of BCO/Co-g-C₃N₄/rGO in up to 5 cycles are facilitated by the synergistic cooperation between BCO and Co-g-C₃N₄, with rGO functioning as a key factor in accelerating the transfer of electrons across the heterojunction.