Development of nano NiO incorporated nickel–phosphorus coatings for electrocatalytic applications

• Nano NiO particles were prepared by wet chemical precipitation method.
• Electroless Ni–P composite coatings were prepared by incorporating nano NiO.
• The composite coatings exhibited excellent physico-electrochemical characteristics.
• The coating exhibited higher hardness, thickness and deposition rate.
• The coating had lower overpotential and enhanced electrocatalytic efficiency.

Nano NiO particles, prepared by wet chemical precipitation method using nickel nitrate as precursor, were characterized using different techniques including XRD, UV spectroscopy, HRTEM, FTIR spectroscopy and Micro Raman spectroscopy. The effects of nano NiO incorporation on enhancement of electrocatalytic efficiency of the electroless Ni–P coatings for hydrogen evolution reactions (HERs) in alkaline medium were systematically investigated in this paper with respect to both metallurgical and electrochemical characteristics. An improvement in the hardness and thickness of electroless coatings along with a mirostructural surface grain refinement was achieved by the incorporation of the nano NiO into the Ni–P matrix. The long term stability of nano NiO incorporated coatings in alkaline medium was ensured by open circuit potential (OCP) analysis. The composite incorporated coatings exhibited a substantial reduction in overpotential during HER studies in 32% NaOH medium. The role of nano NiO on enhancement of electrocatalytic efficiency of the coatings for catalytic HER is evident from the results of potentiodynamic polarization and cyclic voltammetric studies.