Electrochemical nitrate reduction (NITRR) offers a promising alternative toward nitrogen recycling and ammonia production under ambient conditions, for which highly active and selective electrocatalyst is desired. In this study, metallic cobalt nanoarrays as facilely prepared from the electrochemical reduction of Co(OH)₂ nanoarrays (NAs) are demonstrated to exhibit unprecedented NH₃ producing capability from catalyzing NITRR. Benefitting from the high intrinsic activity of Co⁰, intimate contact between active species and conductive substrate and the nanostructure which exposes large number of active sites, the Co‐NAs electrode exhibits current density of −2.2 A cm⁻² and NH₃ production rate of 10.4 mmol h⁻¹ cm⁻² at −0.24 V versus RHE under alkaline condition and significantly surpasses reported counterparts. Moreover, the close‐to‐unity (≥96%) Faradaic efficiency (FE) toward NH₃ is achieved over wide application range (potential, NO₃⁻ concentration and pH). Density function theory calculation reveals the optimized adsorption energy of NITRR intermediates on Co surface over Co(OH)₂. Furthermore, it is proposed that despite the sluggish kinetics of Volmer step (H₂O → *H + *OH) which provides protons in conventional hydrogenation mechanism, the proton‐supplying water dissociation process on Co surface is drastically facilitated following a concerted water dissociation–hydrogenation pathway.

Facilely prepared Cu_xS@NiCo-LDH core–shell nanoarray electrocatalysts exhibit superior bifunctionality towards electrochemical HMF oxidation and H₂ production.

Introduction of A-site deficiency on Ni-doped LaSrCrO ₃ anodes helps form highly mobile oxygen vacancies and remarkably enhances Ni nanoparticle reducibility, and significantly increases electronic conductivity and catalytic activity.