Silver nanoparticle-enhanced photocatalytic CO2 reduction over Ag/Nb2O5 under UV–vis light irradiation

Abstract

A photocatalyst composed of Ag nanoparticles (NPs) supported on pseudo-hexagonal niobium pentoxide (TT-Nb2O5) was synthesized in this study. This catalyst exhibited an enhanced photocatalytic performance for the reduction of CO2 by H2O under UV–vis light irradiation. A CO yield of up to 66.5 μmol·g−1·h−1 with a selectivity of 92.1% were achieved, and also an excellent stability was observed across four cycles. Characterization studies show that the introduction of Ag NPs onto Nb2O5 was beneficial for the formation of oxygen vacancies (Vos) (which were further regenerated when exposed to UV light), resulting in the enhanced adsorption and activation of CO2. The electron-rich Ag NPs were conducive to the formation of Ag-H bonds after the dissociation of H2O to H+, which promoted the proton-electron coupling process for converting the CO2 absorbed at Vos sites into CO. Moreover, the localized surface plasmon resonance (LSPR) of Ag NPs，which was induced by visible light, playing a role in accelerating the decomposition and desorption of *COOH into CO. This work provides new insight into reduction of CO2 by H2O under UV–vis light irradiation.