Screening of metal–organic frameworks for efficient electrocatalytic nitrogen reduction

In this work, 44 metal–organic frameworks (MOFs) are screened for efficient electrocatalytic nitrogen reduction reaction (eNRR). The isosteric heats of N₂ adsorption on the 44 metal active centers of MOFs are calculated by the grand canonical Monte Carlo method. It is found that p-block-elements exhibit the highest N₂ affinity among all screened elements, implying their excellent catalytic potentials for eNRR. Furthermore, the Al element is preferentially chosen as the metal center of MOFs (MIL-53 (Al)) owing to its relatively low toxicity and cost. Combined in situ Diffuse Reflectance Infrared Fourier Transform (DRIFT) analysis with theoretical calculation, we found that N₂ is mainly attracted by the bridging oxygen of Al-O-Al structure in the MIL-53 (Al). The optimized MIL-53 (Al) shows a superior activity with the NH₃ yield rate of 74.55 ± 1 μg h⁻¹ mg_cat⁻¹ at −0.3 V vs. Reversible Hydrogen Electrode (RHE), to our best knowledge, which is currently the highest activity of MOF-based catalyst for eNRR reported in the literature.