Molecular engineering to introduce carbonyl between nickel salophen active sites to enhance electrochemical CO2 reduction to methanol

The electrochemical reduction of CO2 to methanol is a potentially cost-effective strategy to reduce the concentration of this greenhouse gas while at the same time producing a value-added chemical. Herein, we detail a highly efficient 2D nickel organic framework containing a large density of highly dispersed salophen NiN2O2 active sites toward electrochemical CO2RR to methanol. By tuning the ligand environment of the salophen NiN2O2, the electrocatalytic activity of the material toward CO2 reduction can be significantly improved. We prove that by introducing a carbonyl group at the ligand environment of the Ni active sites, the electrochemical CO2 reduction activity is highly promoted and its product selectivity reaches a Faradaic efficiency of 27% toward the production of methanol at − 0.9 V vs RHE. The salophen-based π-d conjugated metal-organic framework presented here thus provides the best performance toward CO2 reduction to methanol among the previously developed nickel-based electrocatalysts.