Efficient Nitrate-to-Ammonia Electroreduction at Cobalt Phosphide Nanoshuttles

The nitrate electroreduction reaction (NO 3 – -ERR) is an efficient and green approach for nitrate remediation, which requires a highly active and selective electrocatalyst. In this work, porous and amorphous cobalt phosphide nanoshuttles (CoP PANSs) are successfully synthesized by using Mg 2+ ion-doped calcium carbonate nanoshuttles (Mg-CaCO 3 NSs) as the initial reaction precursor via precipitation transformation and a high-temperature phosphidation strategy. Various physical characterizations show that CoP PANSs have porous architecture, amorphous crystal structure, and big surface area. Electrochemical measurements reveal for the first time that CoP PANSs have outstanding electroactivity for NO 3 – -ERR in a neutral electrolyte. At an applied potential of −0.5 V vs reversible hydrogen electrode, CoP PANSs can achieve a high Faraday efficiency (94.24 ± 2.8%) and high yield rate (19.28 ± 0.53 mg h –1 mg cat –1 ) for ammonia production, which exceeds most reported values at various electrocatalysts for NO 3 – -ERR. Thus, the present result indicates that cobalt phosphide nanomaterials have promising application for NO 3 – -ERR.