Electrolytic reduction of CO2 in KHCO3 and alkanolamine solutions with layered double hydroxides intercalated with gold or copper

The application of electrocatalytic reduction of CO2 is limited by the low solubility of CO2 in water, separation of products, energy conversion efficiency and insufficient catalyst performance. In this research, enhanced CO2 reduction was observed in alcohol amine solution by using layered double hydroxides (LDHs) intercalated with gold or copper. Copper was found to be distributed more evenly and thus had a larger electrochemical active surface area (ECSA) through the pre-intercalation of EDTA when compared with the direct ion-exchange of [AuCl4]− with LDHs. In 0.5 M KHCO3 solutions, CO and H2 was monitored for Au/MgAl-LDHs while additional products of CH4 and HCOOH was measured by using Cu/MgAl-LDHs. In 1.0 M alcohol amine solutions, CO and H2 were determined as the main products for both Au/MgAl-LDHs and Cu/MgAl-LDHs. Under all the test conditions hydrogen evolution reaction (HER) was enhanced towards negative potential, resulting in a higher Faraday's Efficiency (FE) for H2.