TiC supported Pt-based nanoparticles: Facile sonochemical synthesis and electrocatalytic properties for methanol oxidation reaction

In this study, we synthesized Pt nanoparticles (NPs) with small amounts of Mn (≤11.4 at%) included, hence Pt(Mn) NPs, on titanium carbide (TiC) support (denoted as Pt(Mn)/TiC) in three different Pt loadings (16.0-33.2 wt%) and investigated their electrocatalytic performance for methanol oxidation reaction (MOR) in acidic media. The syntheses were achieved via one-pot sonochemical reactions of Pt(acac)2 and Mn(acac)2 (acac = acetylacetonate) in ethylene glycol in the presence of TiC particles and without any other additives. The Pt(Mn) NPs were uniform in size (4-6 nm) and were evenly deposited on the TiC surface. The electronic structure of Pt in Pt(Mn)/TiC samples, probed by X-ray photoelectron spectroscopy (XPS) and other techniques, is systematically changed with the Pt loading, by which enhanced electrocatalytic properties from pure Pt are expected. In addition, the TiC support contributes to enhancing the electrocatalytic properties of Pt(Mn) NPs through its high conductivity, chemical resistance to corrosion, and the TiO2 formed on the surface which exerts the bifunctional mechanism to reduce the CO poisoning on Pt. The electrochemical performance of Pt(Mn)/TiC was investigated by the rotating disk electrode (RDE) technique. The specific and mass MOR currents are, respectively, 1.6-2.2 and 0.9-1.4 times higher in Pt(Mn)/TiC samples than in commercial Pt/C. All Pt(Mn)/TiC samples show 93-98% of the initial electrochemical surface areas after 3000 potential cycles, superior electrochemical stability to commercial Pt/C (86%).