Enhancing Ethanol Electrooxidation in Acidic Media Using Pt Nanoparticles Supported on Metal Oxide-Modified Vulcan...

Nanocomposite electrode materials based on Pt nanoparticles (Pt NPs) deposited on various carbonaceous materials (Carbon Black-Vulcan XC72, graphene, and graphite) were fabricated and evaluated for ethanol electrooxidation reaction (EOR) in acidic media. The promotional effects of calcination and incorporation of metal oxides (TiO₂, SnO₂, ZnO, Fe₂NiO₄, Fe₂O₃, CuFe₂O₄, ZnFe₂O₄, and 5% Ru on alumina) into Vulcan XC-72 on the performance of Pt NPs toward EOR were systematically evaluated. Pt NPs (∼20 wt %) were synthesized via a facile NaBH₄ reduction method at ambient temperature, yielding spherical nanoparticles with minimal agglomeration. Physicochemical characterization (XRD, TEM, and SEM) confirmed uniform Pt dispersion and reduced particle size on calcined Fe₂O₃-C supports. Electrochemical analysis (CV, CA, LSV, and EIS) revealed that calcined Pt/5% Fe₂O₃-C exhibited superior EOR activity, with a low onset potential (0.2 V vs Ag/AgCl), high current density (0.52 mA/cm²), and enhanced stability (retaining >34% activity after 3000 s). Dual calcination (pre/post-Pt deposition) stabilized ultrasmall Pt NPs (3.09 nm) on Fe₂O₃-C, achieving 2.3 times higher mass activity than Pt/C. The improved performance is attributed to synergistic electronic effects, optimized Pt-support interactions, and Fe₂O₃-mediated C-C bond cleavage. This work highlights the efficacy of dual thermal annealing (pre- and post-Pt deposition) in stabilizing Pt NPs and advancing DEFC catalyst design.