Facile Construction of CuFe-Based Metal Phosphides for Synergistic NO Reduction to NH and Zn-Nitrite Batteries in Electrochemical Cell.

The electrocatalytic nitrite/nitrate reduction reaction (eNORR/eNORR) offer a promising route for green ammonia production. The development of low cost, highly selective and long-lasting electrocatalysts for eNORR/eNORR is challenging. Herein, a method is presented for constructing CuP-FeP heterostructures on iron foam (CuFe-P/IF) that facilitates the effective conversion of NO and NO to NH. At -0.1 and -0.2 V versus RHE (reversible hydrogen electrode), CuFe-P/IF achieves a Faradaic efficiency (FE) for NH production of 98.36% for eNORR and 72% for eNORR, while also demonstrating considerable stability across numerous cycles. The superior performance of CuFe-P/IF catalyst is due tothe rich CuP-FeP heterstuctures. Density functional theory calculations have shed light on the distinct roles that CuP and FeP play at different stages of the eNORR/eNORR processes. FeP is notably active in the early stages, engaging in the capture of NO /NO , O─H formation, and N─OH scission. Conversely, CuP becomes more dominant in the subsequent steps, which involve the formation of N─H bonds, elimination of OH species, and desorption of the final products. Finally, a primary Zn-NO battery is assembled using CuFe-P/IF as the cathode catalyst, which exhibits a power density of 4.34 mW cm and an impressive NH FE of 96.59%.