Synergistic Integration of Amorphous Cobalt Phosphide with a Conductive Channel for Highly Efficient Electrocatalytic Nitrate Reduction to Ammonia

Abstract

Abstract Electrocatalytic nitrate reduction to ammonia (NO 3 RR) is regarded as a viable alternative reaction to “Haber Bosch” process. Nevertheless, it remains a major challenge to explore economical and efficient electrocatalysts that deliver high NH 3 yield rates and Faraday efficiencies (FE). Here, it demonstrates the fabrication of a 3D core‐shell structured Co‐carbon nanofibers (CNF)/ZIF‐CoP for NO 3 RR application. Benefitting from the distinct electron transport property of Co‐CNF and desirable mass transfer ability from amorphous CoP framework, the as‐prepared Co‐CNF/ZIF‐CoP exhibits large NH 3 FE (96.8 ± 3.4% at −0.1 V vs reversible hydrogen electrode (RHE)) and high yield rate (38.44 ± 0.65 mg cm −2 h −1 at −0.6 V vs RHE), which are better than Co‐CNF/ZIF‐crystal CoP. Density functional theory (DFT) calculations further reveal that amorphous CoP presents a lower energy barrier in the rate determination step of the protonation of *NO to produce *NOH intermediates compared with crystal CoP, resulting in a superior NO 3 RR performance. Eventually, an aqueous galvanic Zn–NO 3 − battery is assembled by using Co‐CNF/ZIF‐CoP as cathode material to achieve efficient production of NH 3 whilst simultaneously supplying electrical power. This work offers a reliable strategy to construct amorphous metal phosphide framework on conducting CNF as efficient electrocatalyst and enriches its promising application for NO 3 RR.