Two key problems inhibiting the commercialization of direct methanol fuel cells (DMFCs) are the cost of the precious metals employed and the sluggish kinetics and catalyst poisoning by CO or CHO species. Research to solve the first drawback [1][2][3][4] focuses on the reduction of precious metal loading, which is achieved by increasing the catalysts specific surface area and its accessibility. For the second problem, advanced electrocatalyst design relies on the "bifunctional approach", [5][6][7][8][9][10] in which a second compound such as ruthenium or RuO 2 ·x H 2 O assists the oxidation of CO or CHO species by adsorption of oxygen-containing species close to the poisoned Pt sites. In contrast to previous work on PtRu alloy catalysts, [11][12][13] Rolison and co-workers [14,15] emphasized the importance of hydrous ruthenium oxides because the RuO 2 ·x H 2 O speciation of Ru in nanoscale PtRu blacks shows both high electron and proton conductivity, which results in a much more active catalyst for methanol oxidation. However, direct evidence of the catalytic function of hydrous oxides is very scarce.Mixed proton-electron conducting materials should be ideal catalyst supports for DMFCs since they allow for low ohmic resistance in both the proton and electron conduction at the same time. As hydrous ruthenium(IV) oxide has been reported to contain liquid or liquid-like regions of water to

Two key problems inhibiting the commercialization of direct methanol fuel cells (DMFCs) are the cost of the precious metals employed and the sluggish kinetics and catalyst poisoning by CO or CHO species. Research to solve the first drawback [1][2][3][4] focuses on the reduction of precious metal loading, which is achieved by increasing the catalysts specific surface area and its accessibility. For the second problem, advanced electrocatalyst design relies on the "bifunctional approach", [5][6][7][8][9][10] in which a second compound such as ruthenium or RuO 2 ·x H 2 O assists the oxidation of CO or CHO species by adsorption of oxygen-containing species close to the poisoned Pt sites. In contrast to previous work on PtRu alloy catalysts, [11][12][13] Rolison and co-workers [14,15] emphasized the importance of hydrous ruthenium oxides because the RuO 2 ·x H 2 O speciation of Ru in nanoscale PtRu blacks shows both high electron and proton conductivity, which results in a much more active catalyst for methanol oxidation. However, direct evidence of the catalytic function of hydrous oxides is very scarce.Mixed proton-electron conducting materials should be ideal catalyst supports for DMFCs since they allow for low ohmic resistance in both the proton and electron conduction at the same time. As hydrous ruthenium(IV) oxide has been reported to contain liquid or liquid-like regions of water to

Catalysts H 2000 Novel Nanocomposite Pt/RuO 2 ·xH 2 O/Carbon Nanotube Catalysts for Direct Methanol Fuel Cells. -The title materials are synthesized from aqueous solutions of carbon nanotubes (CNT) coated with sodium dodecyl sulfate and RuCl3 (sonication for 5 min), followed by deposition of Pt using H2[PtCl6] in ethylene glycol (140°C, 3 h). The samples are characterized by XRD, TEM, and electrochemical measurements. The Pt/RuO 2 ·0.56H 2 O/CNT catalyst shows superb performance for direct methanol electrooxidation. -(CAO, L.; SCHEIBA, F.; ROTH, C.; SCHWEIGER, F.; CREMERS, C.; STIMMING, U.; FUESS, H.; CHEN, L.; ZHU, W.; QIU*, X.; Angew.

Metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS(HeI)) and x-ray photoelectron spectroscopy (XPS) were applied to study the interaction of O 2 , CO and CO 2 with Co films at room temperature. The films were produced on Si(100) surfaces under the in situ control of MIES, UPS and scanning tunnelling microscopy (STM). For O 2 , dissociative adsorption takes place initially and then incorporation of oxygen starts at exposures of ∼5 L. Comparison of the MIES and UPS spectra with those published for CoO shows that near-stoichiometric CoO films can be obtained by co-deposition of Co and O 2 . The CO is adsorbed molecularly up to a maximum coverage of ∼0.6 monolayer, with the C-end pointing towards the surface. The CO 2 adsorption is dissociative, resulting in the formation of Co-CO bonds at the surface. The resulting oxygen atoms are mostly incorporated into the Co layer. For all studied molecules the interaction with Co is similar to that with Ni.