C2 product formation in the CO2 electroreduction on boron-doped graphene anchored copper clusters.

A possible remedy for the increasing atmospheric CO2 concentration is capturing and reducing it into valuable chemicals like methane, methanol, ethylene, and ethanol. However, a suitable catalyst for this process is still under extensive research. Small sized copper clusters have gained attention in recent years due to their catalytic activity in the CO2 reduction reaction. Although C2+ products have a higher economic value, the formation of C1 products was investigated most thoroughly. Graphene is a promising support for small copper clusters in the electrochemical reduction of CO2. It exhibits good mechanical and electrical properties, but the weak interaction between copper and graphene is an issue. Our DFT computations reveal that small Cu clusters on the boron-doped graphene (BDG) support are promising catalysts for the electrochemical reduction of CO2. We found facile reaction pathways towards various C1 (carbon-monoxide, formic acid, formaldehyde, methanol or methane) and C2 (ethanol or ethylene) products on Cu4 and Cu7 clusters on BDG. The reactivity is cluster-size tunable with Cu4 being the more reactive agent, while Cu7 shows a higher selectivity towards C2 products.