Palladium-nickel on tin oxide-carbon composite supports for electrocatalytic hydrogen evolution

Abstract

Water electrolysis is virtually the most renewable and sustainable hydrogen production method. The main challenge in the development of alkaline water electrolysis systems is finding low cost electrode materials with efficient and durable performance. Palladium-nickel alloys are attractive for hydrogen evolution reaction (HER) due to their good catalytic activity, lower cost, and chemical and mechanical stability. On the other hand, composites of metal oxides and carbons have high potential as supports and co-catalysts in electrolysis processes due to their electronic properties and bifunctional mechanisms. In this work, three different composite supports, SnO2-KB600, SnO2-KB300, and SnO2-graphene, are synthesised and decorated with PdNi nanoparticles (NPs). XRD and ICP-OES are used to characterise the produced electrocatalysts. Their activity for HER and stability in 8 M KOH is investigated using linear scan voltammetry and chronoamperometry at temperatures from 25 to 85 °C. Charge transfer coefficients, Tafel slopes, exchange current densities, and activation energies are calculated to assess the electrocatalysts’ efficiency for HER. The results are compared with those obtained with Vulcan-supported PdNi NPs electrocatalyst. Overall, they demonstrate that the three studied SnO2-carbon composites are promising supports for metal NPs, being beneficial for the lifetime of the PdNi-based electrocatalysts, and increasing their electroactivity performance in alkaline HER applications.