Two-Dimensional Metal–Organic Framework TM Catalysts for Electrocatalytic N2 and CO2 Reduction: A Density Functional Theory Investigation

Abstract

In this study, we screened novel two-dimensional metal–organic framework (MOF) materials, which can be used as efficient electrocatalysts in the N2 reduction reaction (NRR) and CO2 reduction reaction (CO2RR) through density functional theory (DFT) calculations. By systematically investigating the adsorption behaviors of N2 and CO2 in different MOF-TMs (TM = Fe, Co, Ni, Cu, Zn) and their electrocatalytic hydrogenation processes, we found that 2D MOF-Fe, MOF-Co, and MOF-Ni can be used as catalysts for electrocatalytic NRR. The free energy increase in the corresponding potential-limiting step is calculated to be 0.84 eV on MOF-Fe, 1.00 eV on MOF-Co, and 1.17 eV on MOF-Ni, all of which are less than or at least comparable to those reported values for the NRR. Moreover, only 2D MOF-Fe was identified as a suitable electrocatalyst for CO2RR. Instead of other hydrocarbons, the product CH3OH is selectively obtained in an electrocatalytic CO2 reduction reaction on a 2D MOF-Fe with a free energy increase of 0.84 eV in the potential-limiting step. Overall, the results of this study not only facilitate the potential application of 2D MOF-TMs as electrocatalysts but also provide new guidelines for rationally designing novel electrocatalysts for the NRR and CO2RR.