Shortening the screening process towards high-performance 2D-MOF NRR electrocatalysts with [formula omitted] as the descriptor of N2 activation capability

Abstract

Developing efficient and light pollution electrocatalytic nitrogen reduction reaction (NRR) method for dinitrogen (N2) fixation is a very important and challenging issue in the field of energy and environment. However, the existing multiple-step screening methods for NRR electrocatalysts are inefficient, and it is urgent to search for suitable descriptor to shorten screening process. Herein, by density functional theory (DFT) calculation, the structures, electronic structures and NRR activity of TM3C24X12 (TM-X MOF, TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Mo, X = NH, and S) are investigated, and a descriptor relevant to magnetism Δ(μB_TM-μB_X) is proposed. An “inverted-volcano” relationship between Δ(μB_TM-μB_X) and ΔGN2→NNH reflects direct relevancy between the descriptor and N2 activation capability, leading the way to the two-step screening method. Mo-S MOF is predicted to be the best among catalysts prefer end-on N2 adsorption according to the descriptor, which is verified via a modified three-step screening method, showing that Mo-S MOF has a low limiting potential of −0.41 V and a satisfying activation energy of 0.85 eV in the determining step. The descriptor provides new thoughts for revealing the activity mechanism of 2D-MOF catalysts shortening the screening steps, and finding high-performance catalysts.