Electrochemical water electrolysis using electrodeposited (NiMo) coatings from a low concentration bath

Abstract

Electrodeposited (NiMo) coatings are noted as benign alternative for Pt-free electro-catalysts in alkaline water electrolysis. Hitherto, many Ni-based alloy coatings have been developed using baths of high salts’ concentration. The present paper attempts to see the effect of reducing the metal salt concentrations of a (NiMo) bath on the electro-catalytic functionality of its alloy coatings towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Electro-catalytic performance was evaluated through cyclic voltammetry (CV) and chronopotentiometric (CP) studies and the findings were compared with those obtained from high concentration bath, with the same constituents. It was revealed that the electro-catalytic efficacy of (NiMo) coatings has a direct relation only with the alloy composition, rather than the concentration of the bath, which is due to the inherent induced co-deposition behavior of (NiMo) system, supported by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-Ray Spectroscopy (EDXS), and X-ray Diffraction (XRD) analyses.