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: Carbon-supported catalysts of Pt, Pt/Ru/Pd were evaluated for the electro-oxidation of methanol in phosphoric acid at 180 C using cyclic voltammetry and x-ray diffraction as mentioned in this paper.
Abstract: Carbon-supported catalysts of Pt, Pt/Ru, Pt/Ru/W, and Pt/Ru/Pd were evaluated for the electro-oxidation of methanol in phosphoric acid at 180 C. These catalysts were characterized using cyclic voltammetry and x-ray diffraction. Addition of Ru to a 0.5 mg/cm{sup 2} Pt catalyst (1:1 atomic ratio) caused a large reduction in polarization. The open-circuit voltage was reduced by 100 mV and polarization at 400 mA/cm{sup 2} was reduced by 180 mV. A Pt/Ru (5:2) catalyst with the same Pt content lowered the open-circuit voltage 70 mV. Additions of W to form Pt/Ru/W (1:1:1, atomic ratio) and Pd to form Pt/Ru/Pd (2:2:1), all with the same platinum loading, gave the same performance as Pt/Ru (1:1) without the additions. All of the catalysts showed two Tafel slopes, 140 mV/dec at lower polarizations and 100 to 120 mV/dec at higher polarizations, indicating that the reaction mechanisms are the same for all of the catalysts. Methanol oxidation is greatly enhanced at 180 C in phosphoric acid compared to the lower operating temperatures of a perfluorosulfonic acid electrolyte. The exchange current density for methanol oxidation is higher than that for O{sub 2} reduction. Ru metal dissolves from catalysts at high potentials. Hydrogen oxidation in the presence ofmore » 1 mole percent carbon monoxide showed carbon monoxide tolerance in the order: Pt/Ru/Pd > Pt/Ru > Pt.« less
197 citations
TL;DR: In this article, the addition of platinum to the catalyst enhances selectivity and activity of aldehydes, based on the involvement of lattice oxygen (viz, a Mars and Van Krevelen mechanism) and the spillover of activated hydrogen from the platinum to an oxide.
197 citations
TL;DR: In this paper, the electrochemistry of dissolved oxygen and of superoxide ion in dimethyl-sulfoxide solutions has been studied at platinum, gold and mercury electrodes using voltammetric and chronopotentiometric techniques as well as controlled-potential coulonietry.
196 citations
TL;DR: In this paper, it was demonstrated by X-ray photoelectron spectroscopy (XPS) that oxidized palladium supported on γ-alumina can exist in two chemically different entities, distinguishable by their observed electron binding energies and selective reduction.
Abstract: It was demonstrated by X-ray photoelectron spectroscopy (XPS) that oxidized palladium supported on γ-alumina can exist in two chemically different entities, distinguishable by their observed electron binding energies and by selective reduction. Larger oxidized particles are characterized by a binding energy attributed to PdO. This oxide is reduced to metallic palladium at room temperature in hydrogen, as would be expected for bulk PdO. On the other hand, at low palladium loadings of 0.5 wt.-% and less, the majority of the palladium is present at a binding energy shifted approximately 1.6 eV higher than that observed for PdO. The shift appears to be associated with a metal-support interaction at concentrations where the palladium is highly dispersed. Contrary to that observed at loadings greater than 0.5 wt.-%, this palladium remains mostly oxidized when exposed to hydrogen at room temperature. The results are compared with literature data reported for platinum/γ-alumina.
196 citations
TL;DR: In this article, the performance of metal-free nitrogen-doped porous carbon nanosheets (NPCN) with hierarchical porous structure and a high surface area of 1436.02m 2 ǫg −1 for catalyzing ORR was reported.
196 citations