Constructing well-dispersed active phase via spontaneous redox for electrochemical nitrate reduction to ammonia†

In this study, a distinctive multiple core–shell structure of Co nanoparticles inserted into N-doped carbon dodecahedron@Co hydroxide (Co/NCD@Co(OH)₂) was synthesized via a spontaneous redox reaction between metallic Co and NO₃⁻, ultimately materializing the fine dispersion and exposure of the active sites. The electronic interaction existing between the Co/NCD core and the Co(OH)₂ shell brings a synergistic effect, conspicuously lessens the overpotential, and reinforces the yield-rate and faradaic efficiency of NH₃ for electrochemical nitrate–ammonia conversion. This study underlines the spontaneous redox between the catalysts and substrate, rendering it as a synthetic strategy for designing genuine and well-dispersed active sites.