Synthesis of poly(N-vinyl-2-pyrrolidone) adsorbed-AuPt/C bimetallic nanoparticles and their unusual electrocatalytic activity towards methanol tolerant oxygen reduction reaction

It has been suggested that the presence of adsorbed impurities, such as capping agent or organic reaction products adsorbed on the metallic nanoparticles, severely affects the electrocatalytic activity of surface sensitive reactions. At least in some cases, these adsorbed impurities may alter the electronic nature of nanoparticles and thus alter the electrocatalytic activity. In this work, we report the synthesis of AuPt/C bimetallic nanoparticles (BNPs) supported on Vulcan carbon using the polyol method in the presence of different concentrations of polyvinylpyrrolidone (0.01, 0.1, and 1 %) as a capping agent and electrocatalytic activity of the synthesized AuPt/C BNPs. We found that the PVP adsorbs on the AuPt BNPs through C = O functional group, but not through the Natom. The oxygen reduction reaction (ORR) activity and the methanol tolerance were evaluated on those PVP adsorbed AuPt/C BNPs catalysts. Remarkably, AuPt/C BNPs catalyst with 0.1 % PVP showed a balance of ORR electrocatalysis and methanol tolerance when compared to the PVP free AuPt BNPs. The adsorbed PVP on AuPt BNPs alters the electronic properties of the Pt through electronic interaction with Pt and also controls the surface geometry suitable to ORR, but not the methanol adsorption.