Boosting electrocatalytic N2 reduction by MnO2 with oxygen vacancies

Here, we demonstrate the experimental verification of utilizing a MnO2 with oxygen vacancies (MnOx) nanowire array for high-performance and durable electrocatalytic reduction at neutral pH. Such MnOx nanoarray obtains a high rate of NH3 formation (1.63 × 10−10 mol cm−2 s−1) and a high Faradaic efficiency of 11.40%, which are much higher than those of its pristine MnO2 counterpart (2.3 × 10−11 mol cm−2 s−1; 1.96%). Density functional theory calculations demonstrate that the enhancement of N2 adsorption on the MnOx surface is due to stronger electronic interaction between the N2 molecule and the Mn6c atoms as a result of the oxygen vacancy. This work opens up a new avenue to explore oxygen nonstoichiometry toward the rational design of N2-fixing electrocatalysts with boosted performance for applications.