Grain-Boundary-Rich Copper for Efficient Solar-Driven Electrochemical CO<sub>2</sub> Reduction to Ethylene and Ethanol
Zhiqiang Chen, Tuo Wang, Bin Liu, Dongfang Cheng, Congling Hu, Gong Zhang, Wenjin Zhu, Huaiyuan Wang, Zhi‐Jian Zhao, Jinlong Gong
Abstract
The grain boundary in copper-based electrocatalysts has been demonstrated to improve the selectivity of solar-driven electrochemical CO2 reduction toward multicarbon products. However, the approach to form grain boundaries in copper is still limited. This paper describes a controllable grain growth of copper electrodeposition via poly(vinylpyrrolidone) used as an additive. A grain-boundary-rich metallic copper could be obtained to convert CO2 into ethylene and ethanol with a high selectivity of 70% over a wide potential range. In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy unveils that the existence of grain boundaries enhances the adsorption of the key intermediate (*CO) on the copper surface to boost the further CO2 reduction. When coupling with a commercially available Si solar cell, the device achieves a remarkable solar-to-C2-products conversion efficiency of 3.88% at a large current density of 52 mA·cm–2. This low-cost and efficient device is promising for large-scale application of solar-driven CO2 reduction.