Carbon–CeO2 composite nanofibers as a promising support for a PtRu anode catalyst in a direct methanol fuel cell (original) (raw)
Electrochimica Acta, 2013
Different carbon materials with high electrical conductivity have been studied as electrocatalyst support for direct alcohol fuel cells (DAFCs). The aim of the work was to establish the influence of the support on the catalyst properties and to improve their efficiency in the fuel cell. Carbon nanofibers (CNFs), carbon nanocoils (CNCs) and ordered mesoporous carbons (gCMK-3) have been used for synthesizing platinum catalysts by the polyol method. Results have been compared with those obtained for a platinum catalyst supported on Vulcan XC-72R, prepared by the same method, and for the commercial Pt/C catalyst from E-TEK. It has been demonstrated that novel carbon supports could help to oxidize CO adsorbed on platinum particles more easily than the commercial carbon support and improve the alcohol oxidation reaction, both in terms of onset potential and current density. The catalyst supported on gCMK-3 carbon resulted to be the most effective in both the methanol and ethanol oxidation, which can be attributed to its ordered structure and high electrical conductivity.
Fuel cell performance of Pt electrocatalysts supported on carbon nanocoils
International Journal of Hydrogen Energy, 2014
Polymer electrolyte membrane fuel cell Carbon nanocoils Electrocatalyst a b s t r a c t Carbon nanocoils (CNCs) synthesized via the catalytic graphitization of resorcinolformaldehyde gel were investigated as an electrocatalyst support in PEMFC anodes. Their textural and physical properties make them a highly efficient catalyst support for anodic hydrogen oxidation in low temperature PEMFC.
Applied Catalysis B Environmental
Pt–Ru catalysts supported on carbon nanofibers were synthesized by different synthesis methods: reduction with sodium borohydride, methanol and formate ions (denoted as BM, MeOH and SFM, respectively). The catalyst synthesized by the SFM route was heat-treated (denoted as SFM TT) in order to enhance its catalytic activity, generating in this way a new catalyst. Physical characterization was performed by means of energy-dispersive X-ray (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Results showed that Pt–Ru/CNF catalysts with similar metal content (20 wt%) and atomic ratio (Pt:Ru 1:1) can be obtained by all methodologies. In order to determine the CO tolerance and the electroactive areas of the materials, adsorbed CO stripping experiments were performed. CO stripping curves were modified with the addition of Ru that shifts the onset and peak electrooxidation potentials to more negative values compared with those obt...
Structural designing of Pt-CeO 2/CNTs for methanol electro-oxidation
Journal of Power Sources, 2007
In an attempt to utilize CeO 2 as a co-catalyst with Pt for methanol electro-oxidation, Pt-CeO 2 /CNTs were prepared through structural designing by adsorbing Pt nanoparticles on CeO 2 coated CNTs. X-ray Diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) were used to analyze the composition of the prepared catalysts. Zeta potential analysis, high resolution transmission electron microscopy (HRTEM) and cyclic voltammetry (CV) methods indicated that Pt nanoparticles are selectively adsorbed on CNTs other than CeO 2 surface. Pt-CeO 2 /CNTs were compared with Pt supported on CNTs in terms of electrochemical active surface (EAS) areas, methanol electro-oxidation activity, and chronoamperometry, results indicating that CeO 2 can enhance the catalytic activity of Pt for methanol electro-oxidation with no apparent decrease of EAS. The CO stripping test showed that CeO 2 can make CO stripped at a lower potential, which is helpful for CO and methanol electro-oxidation.
Enhanced methanol electro-oxidation activity of PtRu catalysts supported on heteroatom-doped carbon
Electrochimica Acta, 2008
PtRu nanoparticles deposited on a carbon black substrate are catalysts commonly employed for the electrooxidation of methanol and carbon monoxide-containing hydrogen feeds [1,. However, improvement of effective electrocatalysts is an essential goal in the development of a practical DMFC. The use of carbon black as a support for noble metals is frequent in the electrodes of polymer membrane electrolyte fuel cells, but the impact of the chemical and physical properties of the carbon on electrocatalytic performance are not yet sufficiently understood. The presence of oxygen surface groups influences the surface behaviour of carbons to a considerable extent . As examples, the wettability and adsorptive behaviour of a carbon, as well as its catalytic and electrical properties, are influenced by the nature and extent of such surface groups. The varying role of oxygenated functionalities on the formation of the dispersed platinum has been established [5-8], but not with an additional metal such as ruthenium. In the present investigation we report how the performance in methanol electrooxidation of PtRu nanoparticles deposited on a carbon black substrate, previously functionalized with oxygen surface groups, is improved.
Journal of Power Sources, 2007
Pt particles were prepared through microwave radiation reduction of chloroplatinic acid in ethylene glycol and then adsorbed on carbon nanotubes (CNTs). The thus prepared catalyst was denoted as CNTs-Pt. CeO 2 nanoparticles were prepared through molten salt method. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were used to characterize the morphology and structure of CNTs-Pt and CeO 2 . Cyclic voltammetry (CV), CO stripping and chronoamperometry methods were used to characterize the electrochemical behaviors of the catalysts. The results showed that CeO 2 nanoparticles and CNTs-Pt catalysts can be mixed homogeneously and the current of methanol oxidation can be greatly increased by the mixed CeO 2 nanoparticles. The reason for the increased activity was analyzed and ascribed to the promotion of CO electro-oxidation reaction kinetics by CeO 2 . The method of mixing co-catalyzing materials with Pt-based catalysts is effective and can find wide application in electro-catalysis.
Catalysts, 2013
Different advanced nanostructured carbon materials, such as carbon nanocoils, carbon nanofibers, graphitized ordered mesoporous carbons and carbon xerogels, presenting interesting features such as high electrical conductivity and extensively developed porous structure were synthesized and used as supports in the preparation of electrocatalysts for direct methanol fuel cells (DMFCs). The main advantage of these supports is that their physical properties and surface chemistry can be tailored to adapt the carbonaceous material to the catalytic requirements. Moreover, all of them present a highly mesoporous structure, diminishing diffusion problems, and both graphitic character and surface area can be conveniently modified. In the present work, the influence of the particular features of each material on the catalytic activity and stability was analyzed. Results have been compared with those obtained for commercial catalysts supported on Vulcan XC-72R, Pt/C and PtRu/C (ETEK). Both a highly ordered graphitic and mesopore-enriched structure of these advanced nanostructured materials resulted in an improved electrochemical performance in comparison to the commercial catalysts assayed, both towards CO and alcohol oxidation. OPEN ACCESS Catalysts 2013, 3 672