Support Effect in Bimetallic Particles PtNi for Hydrogen Oxidation Reaction in Alkaline Media

This work reports the synthesis and characterization of platinum-nickel bimetallic particles (Pt Ni) on carbon materials with different structures, such as multi-walled carbon nanotubes (CNT) and Carbon Vulcan XC-72 (C) as electrocatalyst for hydrogen oxidation reaction (HOR). The electrocatalysts were synthesized in two steps; the Ni template was synthesized using a reverse microemulsion method in the first step, and the Pt particles were incorporated in the second step Several physicochemical techniques were used in order to characterize monometallic and bimetallic electrocatalysts as TGA, TEM, DRX, BET, and ICP. Also, the electrocatalysts were studied by electrochemical techniques as anodic CO redissolution and β-NiOOH reduction. The bimetallic electrocatalysts activity was evaluated in the alkaline medium HOR and as anodic electrocatalysts in an AAEMFC. In half cell, the PtNi/CNT show the best activity, better distribution of the nanoparticles increase the surface porosity of the electrocatalyst due to the curvature of the CNT support. While in the AAEMF cell, the PtNi/C electrocatalyst showed a similar performance to the commercial Pt/C, and the PtNi/CNT showed a power density and current density of almost half that of electrocatalysts supported on C. This showed that even though there was a large amount of active sites of both metals in the PtNi/CNT electrocatalyst, the low porosity of catalyst when assembling in the MEA led to the generation of large amounts of water that rapidly flooded the anode compartment of the AAEMF cell, lowering its performance.