Ni@Carbon Nanotubes Derived from Ni-MOF as a Superior Electrocatalyst for Hydrogen Evolution Reaction in Acidic Medium

Hydrogen production through an electrochemical process is a challenging task to realize the renewable energy based technologies such as fuel cells. Herein, we developed a simple, scalable reflux method to synthesis "Ni-CNTs" using Ni-benzene tricarboxylate based metal organic framework (Ni-BTC MOF). Basically, after carbonization under inert atmosphere Ni-BTC MOF leads to the formation of Ni nanoparticles anchored onto carbon nanotubes (Ni-CNTs). Electrochemical studies of such Ni-CNTs exhibited superior electrocatalytic activity for hydrogen evolution reaction (HER) to other Ni–C-based catalysts. It showed an overpotential value of 357 mV at a current density of 10 mA cm–2 in 0.5 M H2SO4. Further, the catalytic activity of thus-synthesized Ni-CNTs-based electrocatalyst can be enhanced by electrochemical potential cycling. Interestingly such activated Ni-CNTs displayed an efficient and improved performance for HER with a lesser overpotential of 261 mV at 10 mA cm–2. With a lower Tafel slope of 88 mV/dec and long-term stability, Ni-CNTs act as a better electrocatalyst in acidic medium. Thus, the proposed work would provide new ways to design electrocatalysts by tuning the properties at the atomic and molecular levels thereby enabling the water electrolysis at large scale.