The interface-mediated electron structure tuning of RuOx–Co3O4 nano-particles for efficient electrocatalytic nitrate reduction

Abstract

The energy-intensive processes for the industrial production of ammonia necessitates the development of new methods to be proposed that will aid in reducing the global energy consumption. Specifically, the electrocatalytic nitrate reduction reaction (NO₃RR) to produce ammonia is more thermodynamically feasible than the electrocatalytic nitrogen reduction reaction (NRR). However, it is hindered by a low catalytic activity due to its complex reaction pathways. Herein, we synthesized a novel electrocatalyst, RuO_x–Co₃O₄ nanoparticles, with abundant interfaces, which exhibited an enhanced catalytic activity for efficient ammonia synthesis. This catalyst delivered a partial current density of 65.8 mA cm⁻² for NH₃ production, a faradaic efficiency (FE) of 89.7%, and a superior ammonia yield rate of up to 210.5 μmol h⁻¹ cm⁻² at −0.6 V vs. RHE. X-ray photoelectron and Raman spectroscopy revealed that the formed interfacial Ru–O–Co bond can decorate the electronic structures of the active sites and accelerate the absorption of NO₃⁻, thus promoting the production of ammonia.