High‐Performance Nitrogen Fixation over Mo Atom Modified Defective α‐MnO₂ (001)

Abstract

The production of ammonia under ambient conditions through electrocatalytic nitrogen reduction reaction is significant but challenging. The lack of an available active NRR electrocatalyst with a high selectivity impedes the development of the electrochemical ammonia synthesis. In this work, via first‐principles density functional theory calculations, we investigated various transition metal atoms (Fe, Cr, V, and Mo) substitution modified defective (with an oxygen vacancy) α‐MnO2 (001) as NRR electrocatalyst. It was found that the incorporation of a single Mo atom substituent at Mn site of α‐MnO2 (001) shows the best performance of nitrogen fixation through enzymatic mechanism with a favorable limiting potential of −0.14 V. The superior selectivity for NH3 over H2 is observed with high Faradaic efficiency of 99 %. The dz2 ‐like characteristics of occupied states around the Fermi level of Mo active center maximizes the p‐d orbital hybridization and thus promotes the stabilities of *N2 and *N2H, which leads to the superior NRR performance. These findings provide theoretical guidance to the development of highly efficient NRR electrocatalysts via defect engineering.