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

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 CO2 -to-C2 H4 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 C2 H4 Faradaic efficiency of 55.1 % at a current density up to 300 mA cm-2 in 1.0 M KHCO3 electrolyte.