Ethylene glycol stabilized NaBH4 reduction for preparation carbon-supported Pt-Co alloy nanoparticles used as oxygen reduction electrocatalysts for microbial fuel cells

Three carbon-supported Pt-Co alloys with varying Pt to Co atom ratio (Pt-2-Co/C, Pt-Co/C, Pt-Co-2/C) were prepared by NaBH4 reduction in ethylene glycol at room temperature. As supported by X-ray diffraction, all the prepared Pt-Co nanoparticles have a single-phase face-centered cubic structure. Transmission electron microscopy indicates that all nanoparticles have small particle-size range and are highly dispersed on carbon support. Catalytic properties of the synthesized Pt-Co alloy catalysts were analyzed using cyclic voltammetry and linear sweep voltammetry methods, and the results suggested that Pt-Co/C catalysts exhibit the best Pt mass activity and the highest stability for the oxygen reduction reaction (ORR) when compared with Pt/C catalyst and other Pt-Co alloy catalyst in both acidic and neutral media. Kinetic analysis reveals that the ORR on Pt-Co alloy follows the four-electron pathway leading to water. As the cathode catalyst, the single-chamber microbial fuel cell tests indicated the much better performance of Pt-Co alloy than that of commercial Pt/C.