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 electrochemical oxidation of ethanol on platinum, rhodium, and platinum−rhodium electrodes was studied using on-line differential electrochemical mass spectrometry (DEMS) and in-situ infrared sp...
Abstract: The electrochemical oxidation of ethanol on platinum, rhodium, and platinum−rhodium electrodes is studied using on-line differential electrochemical mass spectrometry (DEMS) and in-situ infrared sp...
331 citations
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TL;DR: In this article, the authors describe the attachment of metal complexes directly to the exterior of the C[sub 60] framework via solution chemistry forming metal-C[sub60] bonds.
Abstract: This account describes the author's work on the attachment of metal complexes directly to the exterior of the C[sub 60] framework via solution chemistry forming metal-C[sub 60] bonds. Ruthenium, platinum, palladium, and nickel complexes are discussed.
331 citations
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TL;DR: In this paper, the influence of deposited silver upon the photocatalytic activity of titania in the rutile and anatase allotropic forms has been studied in three different reactions.
Abstract: The influence of deposited silver upon the photocatalytic activity of titania in the rutile and anatase allotropic forms has been studied in three different reactions. The common feature found for these three reactions was an electron transfer from illuminated TiO 2 to silver particles. In the first reaction (platinum photodeposition). it has been shown that the initial presence of metallic silver orientates the localization of subsequent Pt photodeposits with, in particular, a 100% selectivity to Pt deposition on top of silver particles or agglomerates previously deposited on anatase. In the second reaction (2-propanol oxidation), Ag deposit was found beneficial for the activity of rutile and detrimental for that of anatase. For rutile which is less active, silver helps for the electron-hole pair dissociation. By contrast, for anatase, the negatively charged Ag particles preferentially attract photoholes and become recombination centers, thus decreasing the photocatalytic activity. For the third reaction (dehydrogenation of 2-propanol), Ag/TiO 2 catalysts were found very poorly active, as expected for a group I-B metal. However, in the additional presence of platinum deposits, Pt/Ag/TiO 2 catalysts are as active as their Pt/TiO 2 homologues, thus confirming that Pt is deposited on top of silver with good electronic contacts between both metals. The three photocatalytic reactions have common electronic processes based on the photoelectron generation on titania and the subsequent electron transfer to the metal (s).
331 citations
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331 citations
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TL;DR: In this paper, the properties of the catalysts denoted as Pt(Pd)/Al2O3(X)-Y (X − calcination temperature of support, ǫ; Y − calcification temperature of catalyst,ǫ) were studied as a function of the temperatures used for calcination of the support and/or the catalyst in oxygen or in a reaction mixture of CO+O2.
Abstract: Platinum and palladium catalysts supported on γ-Al2O3 were studied by XRD, UV–vis DRS, HRTEM, TPR-H2, XPS together with measurements of their catalytic properties. The properties of the catalysts denoted as Pt(Pd)/Al2O3(X)-Y (X—the calcination temperature of support, °C; Y—the calcination temperature of catalyst, °C) were studied as a function of the temperatures used for calcination of the support and/or the catalyst in oxygen or in a reaction mixture of CO + O2. It was found that the deposition of Pt or Pd on γ-Al2O3 did not alter the structure of the support. Two types of the Pt and Pd particles were typically present on the γ-Al2O3 surface: individual particles with dimensions of 1.5–3 nm and agglomerates about 100 nm in size. In the catalysts calcined at relatively low temperatures (Pt/Al2O3(550)-450), platinum was present in the form of metal clusters. However, in the Pd/Al2O3(550)-450 catalyst, the palladium particles were almost completely decorated with a thin layer of an aluminate phase. These structures are not reduced in hydrogen in the temperature range of −15 to 450 °C, and are stable to treatment in a reaction mixture of CO + O2. Pd deposition on the γ-Al2O3-800 support was found to result in stabilization of the active component in two main forms, Pdo and PdO, with varying degrees of interaction due to the decoration effect. Calcination at the low temperature of 550 °C led to the formation of a so-called “core–shell structure”, where a palladium metal core is covered with a thin shell of an aluminate phase. Depending on the calcination temperature of the catalyst in the range of 450–1000 °C, the morphological form of the active component was converted from the “core-shell” state to a state consisting of two phases, Pdo and PdO, with a gradual decrease of the Pdo/PdO ratio, weakening the interaction with the support and the growth of palladium particles. Under the action of the reaction mixture, the Pd/Al2O3(800)-(450,600,800,1000) catalysts underwent changes in the Pdo/PdO ratio, which regulates the light-off temperature. After catalyst calcination at the highest temperature used in this study, 1200 °C, the palladium particles became much larger due to the loss of the palladium interaction with the support. Only the metal phase of palladium was observed in these catalysts, and their catalytic activity decreases substantially.
329 citations