The role of vanadium as a homogeneous catalyst in alkaline water electrolysis

grantor: University of TorontoThe effect of addition of vanadium as a catalyst to the electrolyte in alkaline water electrolysis for the hydrogen evolution reaction on Ni-200 and Ni50Co25P15B10 was investigated. Chronopotentiometry of catalyst concentration ranged 10 to 1000ppm showed an induced change of potential at the Ni-200 cathode which led to a final potential of -1800mV compared a potential of about -2000mV without catalyst. The same potential was reached for Ni50Co25P 15B10 cathodes with 50 to 500ppm catalyst additions. Fe in the electrolyte lowered the overpotential and increased the vanadium catalytic effect slightly to -1710mV. Change in Tafel slope for Ni-200 electrodes after catalyst addition showed a reaction mechanism change. Ni-200 electrodes deactivated as step time of Tafel measurement increased. Electrode surface analysis by SEM showed similar coating morphology for both Ni-200 and Ni 50Co25P15Bl0 electrodes. EDX, XRD and XPS showed the coatings were composed of mixed vanadium species in the V 3+ and V5+ states.M.A.Sc