Nickel nanoflakes on 4-Amino-4H-1,2,4-triazole/graphene for sustainable hydrogen evolution in acid and alkaline media

Abstract

The development of highly active and stable non-noble-metal-based electrocatalysts for the sustainable hydrogen production by hydrogen evolution reaction (HER) in water-splitting cells is now vitally needed. Herein, we design a facile strategy to fabricate the nickel nanoflakes onto 4-Amino-4H-1,2,4-triazole (ATz) functionalized graphene surface through the amidation reaction (Ni/ATz-G) via wet-chemical method. For the development of nickel nanoflakes, nitrogen atoms of ATz which grafted onto graphene sheets are coordinated to nickel atoms initially, and then the formation of nickel nanoflakes is proceeded via epitaxial film growth. Several instrumental characterizations confirm that the nickel nanoflakes are in the Ni(OH)2 form. The as prepared catalyst exhibits remarkable electrocatalytic activity towards the HER while it requires only 48 and 58 mV overpotential to gain current density at 10 mA cm−2 in alkaline and acidic media, respectively. Also it shows improved kinetics and higher stability in both media which makes it a promising catalyst for practical application. The coordination in between nitrogen and nickel nanoflakes and the amidation between ATz and graphene (Ni-N-C system) play a key role in not only intrinsic catalytic activity for HER but also high stability through better grafting of nickel nanoflakes active sites onto the graphene.