Highly efficient electrolytic reduction of nitrate to produce ammonia using Cu@Ni2P-NF Schottky heterojunction

Abstract

Electrolytic reduction of nitrate to produce ammonia (NO3-RR) is one of the very promising alternatives to the energy-consuming Haber-Bosch process. The catalytic activity of nitrate reduction can be effectively improved by tuning the electronic structure and interfacial electron transfer. In this work, Cu@Ni2P-NF metal- semiconductor heterostructure is designed to adjust the adsorption of H* while enhance the adsorption of NO3- through schottky contacts. It is shown that the synergistic effects realized by the built-in electric field could effectively improve the NO3-RR catalytic performance. In the electrolytic cell with 1 M KOH and 20 mM KNO3, the ammonia yield at –0.2 V (vs. RHE) reaches 0.374 mmol∙h−1∙cm−2, and the nitrate removal efficiency is up to 94.63% with a selectivity of 90.25%. The energy conversion is realized by applying a Zn-NO3- battery with power density of 5.09 mW∙cm−2. This work demonstrates that the design of metal-semiconductor schottky heterojunction is an effective way to obtain novel electrocatalysts for NO3-RR.