Operando Reconstruction of CuO/SnO<sub>2</sub> Nanosheets Promotes the Syngas Production from the Electrochemical CO<sub>2</sub> Reduction Reaction
Mengxiao Yan, Tingjie Mao, Tiantian Zeng, Kai Chen, Shun Wang, Juan Wang, Huile Jin
Abstract
Electrochemically reducing CO 2 (CO 2 RR) to high-value chemical products is recognized as a promising route to simultaneously reduce the consumption of fossil fuels and carbon emission. The fabrication of syngas with an appropriate H 2 /CO ratio by CO 2 RR has been widely studied, but the dynamic evolution of the catalyst is still ambiguous. Herein, the reconstruction of CuO/SnO 2 nanosheets (NSs) with a heterojunction structure in the CO 2 RR process was reported by an in situ X-ray diffractometer technique. The products of the CO 2 RR on the optimized CuO/SnO 2 NSs are CO and H 2, achieving a nearly 100% total Faraday efficiency. Moreover, the resulting syngas is maintained at a constant 2:1 ratio of H 2 /CO over a wide potential of −0.8 to −1.2 V versus the reversible hydrogen electrode. Importantly, the detailed characterizations show that Cu 2+ is reduced to Cu during the CO 2 RR process, while the valence state of Sn remains stable. This study presents strong experimental support for the dynamic evolution process of electrocatalysts in other energy conversion fields.