Electrocatalytic Properties of Co-Mo Alloys Electrodeposited from a Citrate-Pyrophosphate Electrolyte

The electrocatalytic activity of electrodeposits of cobalt and Co-Mo alloys in the electroreduction reaction of hydrogen evolution in an acid, neutral and alkaline media has been studied in this work. To deposit coatings, a nontoxic citrate-pyrophosphate electrolyte was used, which was proposed earlier. It has been found that the alloys having the same chemical composition but a different phase composition can exhibit different electrocatalytic activity. The best electrolyte for the making of catalytically active Co-Mo alloys, for which the decrease in hydrogen evolution overpotential as compared with pure cobalt is about 400 mV at 30 mA cm(-2) in alkaline solution, is solution with the cobalt and molybdenum concentration ratio 10:1.