Modification of Carbon Black with Hydrogen Peroxide for High Performance Anode Catalyst of Direct Methanol Fuel Cells

In this study, high-surface-area carbon black is used to support PtRu. In order to increase the functional groups on the surface of carbon black and to have a more homogenous dispersed PtRu metal, the surface of carbon black is functionalized by H₂O₂. PtRu/carbon black is synthesized by the deposition-precipitation method. NaH₂PO₂ is used as the reducing agent in preparation. These catalysts are characterized by N₂ sorption, temperature-programmed desorption, X-ray diffraction, transmission electron microscope, and X-ray photoelectron spectroscopy. The methanol oxidation ability of the catalyst is tested by cyclic voltammetry measurement. Using H₂O₂ to modify carbon black can increase the amount of functional groups on the surface, thereby increasing the metal dispersion and decreasing metal particle size. NaH₂PO₂ as a reducing agent can suppress the growth of metal particles. The best modified carbon black catalyst is the one modified with 30% H₂O₂. The methanol oxidation activity of the catalyst is mainly related to the particle size of PtRu metal, instead of the surface area and conductivity of carbon black. The PtRu catalyst supported by this modified carbon black has very high activity, with an activity reaching 309.5 A/g.