Tuning the Microenvironment in Monolayer MgAl Layered Double Hydroxide for CO₂‐to‐Ethylene Electrocatalysis in Neutral Media

Abstract The electrocatalytic reduction of carbon dioxide provides a feasibility to achieve a carbon‐neutral energy cycle. However, there are a number of bottleneck issues to be resolved before industrial application, such as the low conversion efficiency, selectivity and reaction rate, etc. Engineering local environment is a critical way to address these challenges. Here, a monolayer MgAl‐LDH was proposed to optimize the local environment of Cu for stimulating industrial‐current‐density CO 2 ‐to‐C 2 H 4 electroreduction in neutral media. In situ spectroscopic results and theoretical study demonstrated that the Cu electrode modified by MgAl‐LDH (MgAl‐LDH/Cu) displayed a much higher surface pH value compared to the bare Cu, which could be attributed to the decreased energy barrier for hydrolysis on MgAl‐LDH sites with more OH − ions on the surface of the electrode. As a result, MgAl‐LDH/Cu achieved a C 2 H 4 Faradaic efficiency of 55.1 % at a current density up to 300 mA cm −2 in 1.0 M KHCO 3 electrolyte.