Copper Aluminum Layered Double Hydroxides with Different Compositions and Morphologies as Electrocatalysts for the Carbon Dioxide Reduction Reaction

Abstract Electrochemical CO 2 reduction (CO 2 RR) is a key technology to convert greenhouse gas CO 2 to value‐added products, such as CO and formic acid (HCOOH). In the present study, two‐dimensional Cu‐ and Al‐based layered double hydroxides (Cu−Al/LDHs) were applied as CO 2 RR catalysts. The catalysts were synthesized using a simple co‐precipitation method employing sodium carbonate solutions with different pH and synthesis temperatures. The elemental ratio of Cu and Al, and sheet size were controlled. The most active Cu−Al/LDH showed a faradaic efficiency for CO generation of 42 % and one for formate generation of 22 % at the current density of 50 mA using a gas diffusion electrode system under galvanostatic conditions. Our result indicates that the sheet size of the LDH sheet is a critical parameter for determining CO 2 RR activity.