Effectively Tuning the Ratio of CO and H<sub>2</sub> into Syngas through CO<sub>2</sub> Electrochemical Reduction over a Wide Potential Range on a ZnO Nanosheet via Ni Doping
Jiale Wang, Qian Xiang, Wencong Zhang, Fenglei Shi, Fan Li, Peng Tao, Chengyi Song, Wen Shang, Tao Deng, Jianbo Wu
Abstract
Electrochemical CO2 reduction (ECR) into syngas is a promising method to reduce CO2 in the atmosphere. However, balancing the activity of ECR and hydrogen evolution reaction (HER) and controlling the stable CO/H2 ratios in a large potential range for the industrial desired syngas are still challenging. Herein, a low-cost Ni-doped ZnO nanosheet array on a zinc foil is synthesized via a convenient hydrothermal method to produce a controllable ratio of CO/H2 into syngas. Because of the lower impedance and larger electrochemical area, Ni-doped ZnO has a more significant current density. Furthermore, by adjusting the Ni doping content in the ZnO nanosheet, the activity of ECR and HER could be controlled, and the ratio of CO/H2 can be tuned from 0.1 to 4.5 over a wide potential range (−1.2 to −1.8 V vs reversible hydrogen electrode, RHE), surpassing most of the reported work. Such a wide range and stable ratio of CO/H2 in a broad potential range makes it possible to convert CO2 into feedstock for many essential chemical products.