Synergistic selenium vacancies and bismuth metal centers on Bi2Se3 for enhanced photocatalytic CO2 reduction.

Ultrathin inorganic nanosheets possess a novel electronic structure that enables exceptional performance in the catalytic reduction of carbon dioxide (CO2), representing a promising strategy to mitigate global warming. Bismuth selenide (Bi2Se3) nanosheets are important topological insulators exhibiting high electrical conductivity. Through a solvothermal method followed by hydrogen annealing, selenium-vacancy-rich Bi2Se3 nanosheets with in situ formed bismuth metal clusters are prepared. In this system, surface Se vacancies function as active centers for electron trapping and CO2 adsorption, while Bi metal clusters serve as reactive sites to facilitate charge transfer and catalytic reactions. This dual-functional design establishes a unidirectional electron transfer pathway from selenium vacancies to Bi metal through the topological conductive surface, thereby concentrating electrons at the Bi interface and providing abundant reducing equivalents to enhance CO yield.