Vacancy Engineering of Iron‐Doped W18O49 Nanoreactors for Low‐Barrier Electrochemical Nitrogen Reduction

Abstract

AbstractThe electrochemical nitrogen reduction reaction (NRR) is a promising energy‐efficient and low‐emission alternative to the traditional Haber–Bosch process. Usually, the competing hydrogen evolution reaction (HER) and the reaction barrier of ambient electrochemical NRR are significant challenges, making a simultaneous high NH3 formation rate and high Faradic efficiency (FE) difficult. To give effective NRR electrocatalysis and suppressed HER, the surface atomic structure of W18O49, which has exposed active W sites and weak binding for H2, is doped with Fe. A high NH3 formation rate of 24.7 μg h−1 mgcat−1 and a high FE of 20.0 % are achieved at an overpotential of only −0.15 V versus the reversible hydrogen electrode. Ab initio calculations reveal an intercalation‐type doping of Fe atoms in the tunnels of the W18O49 crystal structure, which increases the oxygen vacancies and exposes more W active sites, optimizes the nitrogen adsorption energy, and facilitates the electrocatalytic NRR.