Enhancement of Pt-Based Catalysts via N-Doped Carbon Supports

This study experimentally examines the enhancement of carbon supported Pt-based catalysts systems via nitrogen doping. It has been reported that nitrogen-containing carbons promote significant enhancement in Pt/C catalyst activity and durability with respect to the methanol oxidation and oxygen reduction reactions. In order to systematically investigate the effect of N-doping, in this work we have developed geometrically well-defined model catalytic systems consisting of tunable assemblies of Pt catalyst nanoparticles deposited onto both N-doped and undoped highly-oriented pyrolytic graphite (HOPG) substrates. N-doping was achieved via ion beam implantation, and Pt was electrodeposited from solutions of H₂PtCl₆ in aqueous HClO₄. Morphology from scanning electron microscopy (SEM) and catalytic activity measurement from aqueous electrochemical analysis were utilized to examine the N-doping effects. The results strongly support the theory that doping nitrogen into a graphite support significantly affects both the morphology and behavior of the overlying Pt nanoparticles. In particular, nitrogen-doping was observed to cause a significant decrease in the average Pt nanoparticle size, an increase in the Pt nanoparticle dispersion, and a significant increase in catalytic activity for both methanol oxidation and oxygen reduction.