Graphene wrapped nickel phthalocyanine nanohybrid: Efficient electrocatalyst for nitrogen reduction reaction

Abstract

Ammonia synthesis is a thermodynamically and kinetically demanding chemical process, and the senescent Haber–Bosch process has been the only way to manufacture ammonia under high pressure and temperature until recently. The electrochemical nitrogen reduction reaction (NRR) is a fungible method of ammonia production that requires strategic tailoring of a highly active, robust, and efficient electrocatalyst to overcome the challenges of high nitrogen (N2) bond dissociation energy, high specific surface area, more catalytic adsorption sites for N2, specificity to produce ammonia (NH3) as a major product, competitive hydrogen evolution reaction (HER), and long-term durability. Herein, Graphene wrapped nickel phthalocyanine (NiPc) nanohybrid (NiPc–RGO) was developed as an electrocatalyst, with a high ammonia yield of 23.9 µg h−1 mg−1cat and a Faradaic efficiency of 18.8 % at −0.3 V vs. RHE, demonstrating outstanding durability and good selectivity. Isotopic labelling studies and numerous control trials are used to establish the validity of nitrogen sources in NH3 generation. These experimental results showed that NiPc-RGO hybrids could potentially serve as efficient NRR electrocatalysts for N2 fixation under ambient conditions.