In-situ construction of S-scheme heterojunction nanoflowers by In2O3-regulated the growth of metal Bi and oxygen vacancy on BiOCl surface for boosting photocatalytic CO2 reduction

The conversion of CO2 into chemicals with value-added can be achieved through the process of photocatalysis, which holds significant importance in the fields of energy and environmental sustainability. Herein, a unique S-scheme In2O3/Bi/BiOCl heterojunction nanoflower with abundant oxygen vacancies was fabricated by a self-assembly strategy, in which the introduction of In2O3 could effectively regulate the in-situ growth of metal Bi and oxygen vacancy on the surface of BiOCl nanosheet. The nanoflower In2O3/Bi/BiOCl photocatalysts exhibited exceptional photocatalytic performance in the CO2 reduction with H2O, ascribing to the synergistic effect of the unique S-scheme heterojunction, the surface plasmon resonance (SPR) effect of metal Bi, and oxygen vacancy engineering. Surprisingly, the In2O3/Bi/BiOCl-4 composites achieved 34.53 μmol⋅g−1⋅h−1 photoreduction efficiency of CO2-to-CO with high selectivity (97.5 %) and high stability, which was 3.12 times higher compared to the pure BiOCl. The S-scheme heterojunction of In2O3/Bi/BiOCl-4 nanoflower can promote carrier separation efficiency and improve light utilization. Meanwhile, the large specific surface area and abundant oxygen vacancies of the nanoflower with 3D/0D/2D structure self-assembly can provide more adsorption and active sites for CO2 photocatalytic reaction. The SPR effect of the in-situ generated metal Bi can further enhance charge transfer to accelerate the photoreduction process of CO2. The present study provides a novel approach for the in-situ construction of S-scheme heterojunction photocatalysts with SPR effect and oxygen vacancies to pursue efficient photocatalytic CO2 reduction in the water phase