Copper aluminum layered double hydroxides with different compositions and morphologies as electrocatalysts for the carbon dioxide reduction reaction.

Electrochemical carbon dioxide (CO 2 ) reduction (CO2RR) is a key technology to convert greenhouse gas CO 2 to value-added products, such as carbon monoxide (CO) and formic acid (HCOOH). In the present study, two-dimensional Copper (Cu) and aluminum (Al) based layered double hydroxides (Cu-Al/LDHs) were applied as CO2RR 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 shows faradaic efficiency for CO generation of 42% and that 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 CO2RR activity.