Development of Water-alkaline Electrolyzer Based on Nickel Alloy Electrodes

Abstract

The electrochemical water splitting is regarded as an appealing method for transforming and storing surplus energy from renewable sources. Nevertheless, the production of hydrogen by water electrolysis is not economically viable. To reduce the cost of the resulting hydrogen, it is necessary to transition from noble-metal catalysts (Pt, Pd, etc.) to more cost-effective alternatives that can guarantee high levels of electrocatalytic activity for both oxygen and hydrogen evolution reactions, while also being more affordable on a per-unit-energy basis. Among transition metals, nickel was selected as the active material due to its low cost and high chemical stability in alkaline media. This work investigates the fabrication and characterization of nanostructured Ni alloy electrodes to reduce the overpotential losses associated with driving the anode oxygen evolution reaction (OER) and the cathode hydrogen evolution reaction (HER) in alkaline environments. Ni alloy nanowires (NWs) with very high surface area and high electrocatalytic activity were prepared by template electrosynthesis. A complete AW laboratory-scale electrolysis system was designed to simultaneously tracks the electrolyser H2 and O2 yield, as well as operating current and voltage. It has been found that alkaline electrolyzers with Ni nanowire electrodes coated with different electrocatalysts have good performance and are stable even at room temperature.