Electrodeposited NiMo, CoMo, ReNi, and electroless NiReP alloys as cathode materials for hydrogen evolution reaction

Abstract Kinetics of hydrogen evolution reaction (HER) is studied on nickel and cobalt-containing electrocatalysts. CoMo, NiMo, and ReNi alloys are obtained by electrodeposition, while NiReP catalysts are prepared by electroless deposition under open-circuit conditions using hypophosphite ions as a reducing agent. The prepared materials are characterized by a complex of modern physical methods; namely, SEM, XPS, XRD, and X-ray absorption spectroscopy. No long-range order was found for all electrodeposited alloys whereas NiReP alloys prepared by electroless deposition contain nickel phosphides. A certain amount of molybdenum or rhenium in the CoMo and ReNi alloys is in the oxidized states. CoMo and ReNi coatings contain 15–20 at. % of oxygen in the form of O2–. Molybdenum containing alloys are instable in the alkaline solutions under electrolysis conditions. In opposite, NiRe electrodeposits are promising candidates for hydrogen evolution catalysis in alkaline solutions due to their high catalytic activity and stability under electrolysis conditions. NiReP alloys can be used for HER catalysis in acidic solutions.