How Acid Washing Nickel Foam Substrates Improves the Efficiency of the Alkaline Hydrogen Evolution Reaction

Abstract

Nickel foam substrates are frequently utilised as porous 3D substrates for renewable energyapplications. The preparation of these substrates usually includes an acid-washing step, but thedegree to which this step affects the final electrochemical performance after spray-coating a catalystink is unreported. Herein, we report the effects of acid washing through physicochemical andelectrochemical characterisation. The electrochemical performance was determined through repeatedmeasurements of catalyst-coated nickel foam substrates both with and without the initial step of acidwashing. It was found that acid washing increased the current density by 17.9% for the acid-treatedMoS2-coated nickel foam electrode. This increment was affiliated with an electrochemically activesurface area that increased by 11.2%, and a Tafel analysis indicated that the acid-treated MoS2-coatedelectrodes facilitated the initial water dissociation step of the hydrogen evolution reaction with greaterease. Similar effects were also discovered for acid-treated PtIr(1:3)/C-coated nickel foam substrates.The stability was also improved; the degradation rate was reduced by 18.9% for the acid-treatedMoS2-coated electrodes. This demonstrates the utility of acid washing nickel foam electrodes.