Preparation and activity of carbon-supported porous platinum as electrocatalyst for methanol oxidation

摘要

In this paper, we reported a novel electrocatalyst, Vulcan XC-72-supported porous platinum nano-particles (Ptp/C) for methanol oxidation. In the preparation of Ptp/C, platinum precursor was first adsorbed on carbon and then reduced by l-ascorbic acid in ethylene glycol solution. The structure and morphology of Pt_p/C and its activity toward methanol oxidation were characterized by transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) measurement, X-ray diffraction (XRD), energy-dispersion spectrometer (EDS), cyclic voltammetry (CV), and chronoamperometry (CA), with a comparison of the electrocatalyst prepared with sodium borohydride as reducer (Pt_s/C). It is found that both electrocatalysts have similar particle size but have different surface morphology of platinum and thus exhibit different electrocatalytic activity toward methanol oxidation. The platinum particle size of both electrocatalysts is 3-5 nm, but the corresponding BET surface areas are different significantly, 131.6 m~2 g~(-1) and 87.7 m~2 g~(-1) for Ptp/C and Pts/C, respectively, indicative of the porous structure of platinum particles in Ptp/C. The peak current for methanol oxidation on CV is 167 mA mg~(-1) and 44 mA mg~(-1) for Ptp/C and Pts/C, respectively, indicative of the high electrocataytic activity of Ptp/C toward methanol oxidation. The result from CA shows that Ptp/C has good stability as the electrocatalyst for methanol oxidation.