Insensitive cation effect on single-atom Ni catalyst allows selective electrochemical conversion of captured CO2 in universal media

Abstract

The direct electroconversion of captured CO2 is attracting attention as an alternative to the current energy-demanding CO2 separation processes. In conventional capturing media, the reaction inevitably takes place in the presence of bulky ammonium, leading to steric hindrance and low CO selectivity. Here, for the first time, we present a single atom Ni catalyst (Ni–N/C) exhibits superior activity for the electroconversion of captured CO2, without the need for additives. In a CO2-captured monoethanolamine-based electrolyte, Ni–N/C achieves a notably high CO selectivity of 64.9% at −50 mA cm−2 integrated with a membrane electrode assembly. We also propose that Ni–N/C demonstrates weak cation sensitivity to the CO2 reduction reaction, maintaining high CO production activity in various capturing solutions, while Ag shows a gradual decrease depending on the bulkiness of the amine. These trends provide insights into selective catalyst design for the electroconversion of captured CO2 in universal media.