Constructing CoAl-LDO/MoO_3-x S-scheme heterojunctions for enhanced photocatalytic CO₂ reduction

Converting CO₂ into chemicals and fuels by solar energy can alleviate global warming and solve the energy crisis. In this work, CoAl-LDO/MoO_3-x (LDO/MO) composites were successfully prepared and achieved efficient CO₂ reduction under visible light. The CoAl-layered double oxides (CoAl-LDO) evolved from CoAl-layered double hydroxide (CoAl-LDH) exhibited a more robust structure, broader light absorption, and improved CO₂ adsorption ability. The local surface plasmon resonance (LSPR) effect excited by nonstoichiometric MoO_3-x broadened the photo-response range of CoAl-LDO/MoO_3-x. In addition, constructing step-scheme (S-scheme) heterojunctions could simultaneously optimize the migration mechanism of photogenerated electrons and holes, and retain carriers with strong redox ability. Therefore, the production rates of CO and CH₄ on the optimal LDO/MO composite were 7 and 9 times higher than the pristine CoAl-LDH, respectively. This work hybridizes oxidation photocatalysts and LDO-based materials to optimize the charge separation and migration mechanisms, which guides the modification of LDO-based materials.