Engineering the Metal‐Support Interaction and Oxygen Vacancies on Ru@P‐Fe/Fe<sub>3</sub>O<sub>4</sub> Nanorods for Synergetic Enhanced Electrocatalytic Nitrate‐to‐Ammonia Conversion
Jinhui Su, Ke Shi, Baocang Liu, Zichao Xi, Junchao Yu, Xuan Xu, Peng Jing, Rui Gao, Jun Zhang
Abstract
Abstract Ruthenium (Ru) loaded catalysts show high activity and selectivity for ammonia (NH 3 ) synthesis via electrochemical reduction of nitrate (NO 3 − ), but their practical application is still restricted by their high cost and insufficient stability. Herein, a multi‐component electrocatalyst of Ru nanoclusters loaded on phosphorus‐doped/phosphate‐modified and oxygen vacancy (O V )‐rich Fe/Fe 3 O 4 composite nanorods (Ru@P‐Fe/Fe 3 O 4 ) to synergistically promote electrocatalytic NO 3 − reduction reaction (NO 3 − RR)‐to‐NH 3 performance via strong metal‐support interaction (SMSI) is reported. Impressively, the best Ru@P‐Fe/Fe 3 O 4 catalyst exhibits outstanding NO 3 − RR activity, selectivity, and durability in 0.1 M KNO 3 + 0.5 M KOH solution, with an NH 3 yield rate of 14.37 ± 0.21 mg NH3 h −1 cm −2 (1710.71 ± 25 mg NH3 h −1 mg Ru −1 ) at −0.75 V versus reversible hydrogen electrode (vs. RHE), an NH 3 Faradaic efficiency (FE) of 97.2% at −0.55 V vs. RHE, and a superior stability over 50 h, suppressing most of reported Fe‐based and Ru‐based electrocatalysts. The characterizations and theoretical calculations unveil that the SMSI between Ru nanoclusters and P‐Fe/Fe 3 O 4 composite nanorods can promote the generation of O V , tune the electronic structure of Ru species, and stabilize Ru nanoclusters, thereby reducing the reaction energy barrier of NO 3 − RR‐to‐NH 3 , inhibiting the competitive hydrogen evolution reaction, and boosting the NH 3 yield rate NH 3 FE, and stability.