AuAg plasmonic nanoalloys with asymmetric charge distribution on CeO2 nanorods for selective photocatalytic CO2‐to‐CH4 conversion

Abstract Converting CO 2 under mild conditions by employing semiconductor photocatalysts is promising to address global environmental issues. However, the current CO 2 conversion efficiency is limited by the difficulty activating the thermodynamically stable CO 2 molecules. Constructing plasmonic nanoalloy‐based photocatalytic systems with significant localized surface plasmon resonance (LSPR) is full of potential but remains a vast challenge. In this work, AuAg plasmonic nanoalloys were incorporated on CeO 2 nanorods (designated as AuAg–CeO 2 ) to achieve selective photoreduction of CO 2 . The result displays that Ag can serve as a superior electron modifier to promote the electron enrichment of Au, thus producing asymmetric charge distributions to boost the selective conversion of CO 2 . Furthermore, the improved LSPR effect on AuAg–CeO 2 induces the generation of high‐energy hot electrons under irradiation, enhancing the reactivity of electrons for CO 2 photoreduction. Due to the aforementioned effects, AuAg–CeO 2 exhibits a high CO 2 ‐to‐CH 4 performance of 92.6 μmol g −1 through a 3‐h test and a high CH 4 selectivity of 94.5%, up to 2.6, 8.7, and 17.1 times higher than the activity of Au–CeO 2 , pure CeO 2 , and Ag–CeO 2 , respectively. This work can provide a new perspective for constructing high‐performance catalysts for photocatalytic CO 2 reduction.