Abstract
The direct methanol fuel cell (DMFC) is a low temperature fuel cell. It can be used for mobile applications. The advantages of direct methanol fuel cells (DMFC) over hydrogen fuel cells include easy storage of the high energy density liquid fuel. CO can adsorb very strongly on the Pt surface in the fuel cell anode, blocking the active sites and causing a large decrease in the electrode performance.PtRu alloys are currently the most active anode catalyst for the oxidation of methanol.To achieve economical Pt loadings in the MEA the electrocatalysts are supportedon high surface area carbon support with a high mesoporous area. The support material must provide a high electrical conductivity, give good reactant gas access to the electrocatalyst, and also show good corrosion resistance. Carbon nanotubes are prominent materials that exhibit special properties which make them suitable for application in several technological areas.Carbon nanotubes have been studied as an electrocatalyst support for direct methanol fuel cells (DMFCs).The common criteria for a high catalyst are: (1) a narrow nanoscale size distribution; (2) a fully alloyed degree; (3) high dispersion on carbon support; (4) low cost. All of these chemical reduction methods include a chemical step for forming nanoparticles, and a deposit step for dispersing the catalyst onto the carbon particles. We use Ethylene glycol as a reductive agent here.The catalysts were characterized by transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma-mass spectrometer (ICP-MS). Their electrochemical behaviors in a half cell are analyzed by cyclic voltammetry (CV).Because the pristine surface of CNTs is inert, it is difficult to attach metal nanoparticles to the substrate surface. Through surface pre-treatments, the metal nanoparticles could easily attach onto the CNTs surface. In order to achieve high dispersion and maximum utilization, we use ethylene glycol as a reductive agent. The results show that the synthesis solution pH is a key factor that influences the catalyst particle size. Heat treatments at these “low” temperatures free up valuable catalyst sites without resulting in changes of the PtRu catalyst properties.After air treated, CO poisioning is obvious.