The effect of pH on electrocatalytic properties of electrodeposited Ni–Mo/Ni coating using 1-ethyl-3-methylimidazolium bromide

In this research, Ni–Mo/Ni coating was deposited by electrodeposition in the modified watts bath containing 1-Ethyl-3-Methylimidazolium Bromide (EMIM [Br]) ionic liquid, followed by studying the effects of pH on the phase formation, morphology, particle size and electrocatalytic properties of Ni–Mo/Ni alloy coating for methanol oxidation reaction (MOR). It was found that by increasing the pH value, Mo content in the structure increases and leading to the conversion of its crystalline structure to an amorphous structure and also reduction of crystallite size. The electrocatalytic results of Ni–Mo/Ni coatings showed that the catalytic activity in the presence of methanol is considerably increased. Also, investigation of the coatings in different pH values in the presence of ionic liquid showed a high anodic current density (15.38 mA cm⁻²) and low onset oxidation potential (0.35 V) at pH 7, suggesting a high catalytic activity at this pH value. (paper)