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

Abstract

The electrochemical reduction of CO 2 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 NiN 2 O 2 active sites toward electrochemical CO 2 RR to methanol. By tuning the ligand environment of the salophen NiN 2 O 2 , the electrocatalytic activity of the material toward CO 2 reduction can be significantly improved. We prove that by introducing a carbonyl group at the ligand environment of the Ni active sites, the electrochemical CO 2 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 CO 2 reduction to methanol among the previously developed nickel-based electrocatalysts. A 2D nickel organic framework containing a large density of highly dispersed salophen NiN2O2 active sites has been synthesized. 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 high Faradaic efficiency of 27% toward the production of methanol at − 0.9 V vs RHE. • We report a novel atomically dispersed nickel catalyst with NiN 2 O 2 structure for efficient production of methanol. • The obtained catalyst gives the highest FEs with 27% (methanol) among Nickel electrocatalysts for CO 2 RR. • We report a new strategy for tuning the electronic structure of catalysts.