Design And Characterization Of Electrocatalysts For Methanol Oxidation Reaction

DMFC has plenty of advantages such as high energy density, low working temperature, and convenience on adding fuels, it is promising to be used in portable electronic devices. While the biggest obstacle for DMFC’s commercialization is that the anode reaction rate is much slower than PEMFC’s, which result in that the power of DMFC is much lower than that of PEMFC, even though methanol has a high energy density. Finding a method which is simple and environment friendly to synthesis methanol electro-oxidation catalyst is meaningful for the DMFC’s development. The study on what happened on Graphene/electrolyte surface in electro-system will have a positive effect on the methanol electro-oxidation catalyst optimization, as grapheme is a usually used support in electro-catalyst,The main content and conclusion of each part is listed as follow:1. The Preparation of Surfactant-free Pt and PtRu Nanoparticles with high Activity for Methanol Oxidation. A green and simple approach for preparing highly active nanocatalysts for MOR has been described. MWCNTs supported Pt nanoparticles with ca.5nm in diameter have been synthesized by using CO as both the reducing and protecting agent. The elimination of organic molecules as either capping agent, reductant or solvent avoids the poisoning effect by such species, whose complete removal from such NPs is very difficult.16.3%Pt/MWCNTs displays high activity for methanol oxidation with peak current density of869mA mg-1Pt and11.6mA cm-2. Ru with various of loading is deposited onto16.3%Pt/MWCNTs by potential sweeping from0.05V to0.4V for various cycles. The best PtRu cacatalyst has Nominal PtRu ration of1:1, at which the onset potential for MOR is0.4V and its mass activity is ca.3times better than that at16.3%Pt/MWCNTs, which displays very good long term stability for methanol oxidation. Our results demonstrate that the strategy with CO ad both reducing and capping agent, is a promising technique for preparing highly active fuel cell catalysts.2. An Electrochemical In-situ Infrared Spectroscopic Study of Graphene/Electrolyte Interface Under Attenuated Total Reflection Configuration. The interface of electrodes composed of5ML Graphene deposited on Si prism in0.1M HClO4in a wide potential window from0.05V to3.0V is examined by electrochemical in-situ infrared spectroscopy under Attenuated-Total-Reflection configuration (EC-ATR-FTIRS). Three bands at1230,1630and3300cm-1were observed when significant anodic current flows at E>2.0V. Both cyclic voltammetric and spectroscopic signals reveal that i) the oxidation of water to oxygen and the oxidation of graphene occur at E>2.0V ii) the defects of graphene is probably the active sites for water oxidation at the graphene. The potential of the application of large scale graphene as a versatile support for nanocatalysts in EC-ATR-FTIRS studies is discussed.