Topic
Platinum
About: Platinum is a research topic. Over the lifetime, 49675 publications have been published within this topic receiving 1150035 citations. The topic is also known as: Pt & element 78.
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TL;DR: In this paper, the catalytic activity of single-phase polycrystalline Pt-Ru bulk alloys toward the electrooxidation of methanol in sulfuric acid electrolyte at room temperature was measured for the first time on well-characterized alloy surfaces, in terms of surface composition and true surface area.
Abstract: The catalytic activity of single-phase polycrystalline Pt-Ru bulk alloys toward the electrooxidation of methanol in sulfuric acid electrolyte at room temperature was measured for the first time on well-characterized alloy surfaces, in terms of surface composition and true surface area. Sputter-cleaned and annealed alloys were prepared in ultrahigh vacuum (UHV) and the surface composition of oxygen-free surfaces was assessed via low-energy ion scattering (LEIS). Pt-Ru alloy surfaces annealed in UHV were strongly enriched in Pt, whereas the surface composition of sputter-cleaned alloys was essentially identical to their bulk composition. It was shown that the sputter-cleaned alloy with a Ru surface of [approx equal] 10 atomic % gave the highest catalytic enhancement (over pure Pt) for the steady-state electrooxidation of methanol at 25[degree]C and 0.5 V, viz., by a factor of 12 in 5.0 mM CH[sub 3]OH solution and by a factor of 30 in 0.5 M CH[sub 3]OH. It was found that the balance between the rate of methanol adsorption and the rate of the oxidative removal of dehydrogenated fragments determines the activities of Pt-Ru alloys with different Ru surface compositions. 51 refs., 9 figs., 2 tabs.
875 citations
Patent•
28 Apr 1971TL;DR: In this paper, the authors proposed a method to construct a PLATINUM-SILOXANE COMPLEX of UNSATURATED SILOXANES, which are useful as HYDROSILATION CATALYSTs.
Abstract: PLATINUM COMPLEXES OF UNSATURATED SILOXANES ARE PROVIDED WHICH ARE USEFUL AS HYDROSILATION CATALYSTS. THESE PLATINUM-SILOXANE COMPLEXES MUST CONTAIN LESS THAN ABOUT 0.1 GRAM ATOM OF HALOGEN, PER GRAM ATOM OF PLATINUM, AND PREFERABLY SUBSTANTIALLY FREE OF HALOGEN WHICH INCLUDE PLATINUM-SILOXANE COMPLEXES WHICH ARE SUBSTANTIALLY FREE OF INORGANIC HALOGEN. THESE PLATINUM-SILOXANE COMPLEXES CAN BE MADE BY EFFECTING CONTACT BETWEEN A PLATINUM HALIDE AND AN UNSATURATED SILOXANE, FOR EXAMPLE, 1,3-DIVINYLTETRAMETHYLDISILOXANE, AND REMOVING AVAILABLE INORGANIC HALOGEN FROM THE RESULTING MATERIAL. IN ADDITION, CURABLE ORGANOPOLYSILOXANE COMPOSITIONS ARE PROVIDED COMPRISING AN ORGANOPOLYSILOXANE POLYMER AND AN EFFECTIVE AMOUNT OF SUCH PLATINUM-SILOXANE COMPLEX.
870 citations
ENEA1
TL;DR: In this article, a detailed procedure for comparing high surface Pt/C catalysts was pointed out, and the real platinum metal surface area was evaluated by cyclic voltammetry on a thin porous coated disk electrode.
863 citations
TL;DR: A robust and highly active catalyst for hydrogen evolution reaction that is constructed by in situ growth of molybdenum disulfide on the surface of cobalt diselenide, which is the best among the non-noble metal hydrogen evolution catalysts and even approaches to the commercial platinum/carbon catalyst.
Abstract: There is substantial research into new catalysts for electroreduction of water. Here, the authors report a robust and active molybdenum disulfide/cobalt diselenide hydrogen evolution catalyst with onset potential of 11 mV and Tafel slope of 36 mV per decade, approaching the activity of platinum.
854 citations
TL;DR: In this paper, the Pt/C catalyst layer of polymer electrolyte fuel cell electrodes have been developed that substantially increase the utilization efficiency of the catalyst, and the performance of fuel cells based on the thin film catalyst layers are comparable with those of gas diffusion electrode designs that utilize several times as much platinum, thus the specific catalysts in the new structures are significantly higher.
Abstract: New structures for the Pt/C catalyst layer of polymer electrolyte fuel cell electrodes have been developed that substantially increase the utilization efficiency of the catalyst. Fabricating the catalyst layers and gas diffusion backings separately makes it possible to formulate each structure with the properties that are most suitable for its function. In the case of the catalyst layer, the optimal properties are hydrophilicity, thinness, uniformity, and the proper ratio of ionomer and supported catalyst. The catalyst layers are cast from solution as thin films that utilize the ionomer itself as a binder. The thin films are hot pressed directly onto the ionomer membranes, and the hydrophobic gas diffusion backings are inserted when the cells are assembled. The performances of fuel cells based on the thin film catalyst layers are comparable with those of gas diffusion electrode designs that utilize several times as much platinum, thus the specific activities of the Pt catalysts in the new structures are significantly higher.
848 citations