Synergistic Mechanism and Regeneration Strategy of Bi-BiOBr@CNF for Photocatalytic CO2 Reduction

The photocatalytic reduction of CO 2 to CO is often constrained by suboptimal visible-light harvesting, interfacial recombination losses, and durability under repeated cycling. Here we design a Bi–BiOBr@CNF architecture that integrates metallic Bi (for plasmon-assisted excitation and interfacial electron transfer), oxygen/bromine vacancies (for CO 2 adsorption/activation), and a conductive CNF network (for dispersion and transport). Photoelectrochemical characterizations elucidate the synergistic mechanism. Under visible light, the catalyst delivers CO as the single detectable product with high selectivity; cycling tests reveal performance decay that is mechanistically linked to defect evolution, and a moderate-temperature regeneration restores activity. The results elucidate the respective roles of Bi 0 , O V , Br V , and the CNF scaffold within an integrated mechanistic framework, and indicate a viable strategy for durable photocatalytic reduction of CO 2 to CO.