Unique dendritic Bi2S3 with ultrathin nanosheets rich in S vacancy-defects toward promoting highly efficient photothermal CO2 reduction into CO

Abstract

The catalytic reduction of carbon dioxide (CO₂) into value-added chemicals utilizing solar energy is a promising strategy to simultaneously address global warming and the energy crisis. The tree-like Bi₂S₃ catalytic material, supported by nanotubes with ultrathin nanosheets as reaction sites, was convincingly synthesized. The ultrathin structure can shorten the transfer distance of charge carriers from the interior onto the surface and reduce the recombination in the body compared to the bulk material. To promote the activation of the reactant, the precursor samples were annealed to form sulfur defect engineering on the nanosheets' surface. Both the DFT calculations and in situ FTIR spectra indicate that the introduction of S vacancies into Bi₂S₃ leads to charge accumulation that effectively traps the formed *COOH molecules, which enriches the catalyst surface with key reaction intermediates, facilitating the photothermal CO₂ reduction reaction.