The activity of the methanol oxidation reaction of a multiwalled carbon nanotube (MWCNT)-supported PtRu catalyst was investigated and compared with the Vulcan XC-72 carbon-supported catalyst. The PtRu nanoparticles with 1:1 and 7:3 atomic ratios (with similar PtRu loadings and morphological structures) were deposited both on the MWCNTs and on the carbon. Cyclicvoltammetry results demonstrated that the MWCNT-supported PtRu catalyst exhibited a higher mass activity (mA mg(-1) of PtRu) for the methanol oxidation reaction than the carbon-supported PtRu under the condition that both catalysts possess more or less the same PtRu loadings, particle sizes, dispersions, and electrochemical surface area. The direct methanol fuel cell performance test data showed that MWCNT-supported PtRu catalysts yielded about 35-39% higher power densities than the carbon-supported PtRu.

No abstract

No abstract

The direct methanol fuel cell (DMFC) enables the direct conversion of the chemical energy stored in liquid methanol fuel to electrical energy, with water and carbon dioxide as by-products. Compared to the more well-known hydrogen fueled polymer electrolyte membrane fuel cells (H 2 -PEMFCs), DMFCs present several intriguing advantages as well as a number of challenges.This review examines the technological, environmental, and policy aspects of direct methanol fuel cells (DMFCs). The DMFC enables the direct conversion of the chemical energy stored in liquid methanol fuel to electrical energy, with water and carbon dioxide as byproducts.Compared to the more well-known hydrogen fueled PEMFCs, DMFCs present several intriguing advantages as well as a number of challenges. Factors impeding DMFC commercialization include the typically lower effi ciency and power density, as well as the higher cost of DMFCs compared to H 2 -based fuel cells. Because of these issues, it is likely that DMFC technology will fi rst be commercialized for small portable power applications (e.g., the displacement of batteries in consumer electronic applications), where the shorter product lifetimes ( ∼ 1-2 yrs for a battery versus 8-15 yrs for a car) and the much higher price points ( ∼ $10/W for a laptop battery vs. ∼ $0.05/W for a vehicle engine) provide a more attractive entry point. While such applications are not likely to signifi cantly impact the global energy sustainability picture, they provide an important initial market for fuel cell technology. As such, in this review, we provide an overview of recent research and the challenges to the development of DMFCs for both the portable (shorter-term) and transport (longer-term) sectors.

Platinum nanocatalysts supported on Vulcan XC-72 carbon have been synthesized through the reduction of chloroplatinic acid with formic acid, using surfactant tetraoctylammonium bromide (TOAB) as the stabilizer in the solvent tetrahydrofuran (THF). These nanocatalysts are synthesized by changing the molar ratio of TOAB to chloroplatinic acid, i.e., N/Pt ratio of 0.76, 0.38, and 0.19. A control catalyst that does not contain TOAB is also synthesized by this method for comparison purposes. Comparison of the morphological properties of these catalysts by transmission electron microscopy (TEM) reveals that the N/Pt ratio of 0.76 catalyst has well-separated smaller particles (2.2 nm) than the other lower molar ratio and control catalysts. X-ray diffraction (XRD) analysis indicates the presence of platinum in the fcc phase and the average size of the particles calculated from the XRD peak widths agreed well with the TEM results. X-ray photoelectron spectroscopic (XPS) measurement of the 0.76 ratio catalyst reveals that a higher amount of Pt exists in its metallic state (73.64% of Pt(O) and 26.36% Pt(II)) and the data are on par with that of the E-TEK catalyst. Stabilization effect of the TOAB on the surface of platinum particles has been discussed with respect to the different N/Pt molar ratios. The XPS technique has been exploited to prove the presence of coverage of TOAB and its subsequent removal from the surface of the Pt particles, which is considered to be the crucial step prior to the electrochemical measurements. Electrochemical measurements have demonstrated that the surface area of the 0.76 ratio catalyst is higher than that of the lower molar ratios (0.38 and 0.19).

No abstract

No abstract

No abstract