Sulfur doped In2O3-CeO2 hollow hexagonal prisms with carbon coating for efficient photocatalytic CO2 reduction

Abstract

Developing integrated photocatalysts with advanced structures and desired components is an effective strategy for promoting solar-to-chemical energy conversion. Herein, a novel sulfur-doped In2O3-CeO2 hollow hexagonal prism with a thin carbon coating (S-C/In2O3-CeO2 HHP) is synthesized by directly pyrolyzing Ce-doped In-Materials of Institute Lavoisier-68 (In-MIL-68) hexagonal prism metal–organic frameworks under N2 atmosphere in the presence of sulfur powder, showing excellent photocatalytic carbon dioxide (CO2) reduction efficiency. This synthetic strategy realizes the regulation of structure, components, and surface defects of the final products. The synergistic effects of hollow porous hexagonal prism structure, In2O3-CeO2 heterojunction, and surface defects exhibit advantageous features for CO2 photoreactions with accelerated transfer and separation of charge carriers, enhanced visible-light utilization and CO2 chemisorption ability, and enlarged catalytic active sites. Benefiting from these advantages, the obtained optimized S-C/In2O3-CeO2 HHP exhibits superior gas phase photocatalytic performance for the conversion of CO2 into CH4 and CO, yielding a CH4 yield of 60.6 μmol g−1h−1 and a selectivity of 92.4% under AM1.5 irradiation without noble metal and organic photosensitizer. This work presents a strategy for the rational design and fabrication of efficient photocatalysts with advanced hollow architectures.