Preparation of Platinum Supported on Carbon Blacks With Different Surface Chemical Characteristics

In a study of the preparation of Pt/C eletrocatalysts, a set of modified Vulcan XC-72R carbon black supports have been prepared by nitric acid or hydrogen peroxide oxidation, or thermal treatment in nitrogen flow. The supports obtained by these methods had largely identical pore structure, but different from the amount of surface oxygen-containing groups. The physical and surface chemical nature of the supports was characterized by XPS, BET, FTIR and acid-base titration. The above pre-treatment-carbon supported platinum catalysts were prepared by impregnation-reduction method with formaldehyde as the reducing agent, H₂PtCl₆ as precursor. The effect of the amount of surface oxygen-containing groups of Vulcan XC-72R carbon black on Pt/C catalysts dispersion was studied by the characterization with XRD and TEM. It has been found that decreasing the amount of surface oxygen-containing groups on carbon supports favored the platinum dispersion on the Pt/C catalysts.