Synthesis and characterisation of Pt–Sn–Ni–Ru and Pt–Sn–Ni–Ga heterogeneous multi-metal electrocatalysts for the electrochemical reforming of ethanol

Ethanol electroreforming is recognized as an innovative and energy-efficient method for hydrogen production. Nevertheless, the rapid poisoning of active sites and the high cost of pure platinum (Pt) hinder its commercial viability. To address these issues, this study investigates the incorporation of secondary metals (Ni, Sn, Ga, and Ru) into Pt/C electrocatalysts to create anodes that are efficient, stable, and cost-effective. The thermal decomposition of polymeric precursors was employed to synthesize the multimetallic electrocatalysts, resulting in spherical nanoparticles ranging from 4 to 6 nm in diameter. The materials were evaluated by physicochemical characterization, cyclic voltammetry, chronoamperometry, and gas-generation tests conducted in an H-cell. Structural analyses suggested the incorporation of promoter metals into the platinum crystal structure as well as the presence of metallic oxide phases. Electrochemically, the quaternary Pt61Sn3Ni17Ru19/C catalyst exhibited remarkable performance: it lowered the oxidation onset potential (-0.63 V vs. Hg/HgO), achieved peak current densities as high as 53.97 mA cm− 2, and exhibited the lowest surface-poisoning rate. In the electroreforming tests, conducted with a 1 cm² platinum black carbon cloth electrode at the cathode, this catalyst produced the largest volume of gas (12.0 mL) in 30 min, while the Pt37Sn8Ni16Ga39/C system attained the highest Faradaic efficiency (97.1%). The findings indicate that the synergistic interactions of the promoter metals activate the bifunctional mechanism and the ligand effect, which consistently refresh the electrode surface. As a result, multimetallic formulations reduce the swift deactivation associated with pure platinum, positioning the Pt-Sn-Ni-Ru system as a strong and efficient alternative for sustainable hydrogen production.