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.
Effects of N-doping Methods on the Microstructure and Oxygen Reduction Performance of Carbon Materials