Highly Selective Photoreduction of CO<sub>2</sub> with Suppressing H<sub>2</sub> Evolution by Plasmonic Au/CdSe–Cu<sub>2</sub>O Hierarchical Nanostructures under Visible Light
Hongzhi Wang, Hongpan Rong, Dong Wang, Xinyuan Li, Erhuan Zhang, Xiaodong Wan, Bing Bai, Meng Xu, Jiajia Liu, Jia Liu, Wenxing Chen, Jiatao Zhang
Abstract
Abstract Here, the photocatalytic CO 2 reduction reaction (CO 2 RR) with the selectivity of carbon products up to 100% is realized by completely suppressing the H 2 evolution reaction under visible light (λ > 420 nm) irradiation. To target this, plasmonic Au/CdSe dumbbell nanorods enhance light harvesting and produce a plasmon‐enhanced charge‐rich environment; peripheral Cu 2 O provides rich active sites for CO 2 reduction and suppresses the hydrogen generation to improve the selectivity of carbon products. The middle CdSe serves as a bridge to transfer the photocharges. Based on synthesizing these Au/CdSe–Cu 2 O hierarchical nanostructures (HNSs), efficient photoinduced electron/hole (e − /h + ) separation and 100% of CO selectivity can be realized. Also, the 2e − /2H + products of CO can be further enhanced and hydrogenated to effectively complete 8e − /8H + reduction of CO 2 to methane (CH 4 ), where a sufficient CO concentration and the proton provided by H 2 O reduction are indispensable. Under the optimum condition, the Au/CdSe–Cu 2 O HNSs display high photocatalytic activity and stability, where the stable gas generation rates are 254 and 123 µmol g −1 h −1 for CO and CH 4 over a 60 h period.