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.

Meso-structured platinum thin films: active and stable electrocatalysts for the oxygen reduction reaction.

Abstract: Improving both the activity and the stability of the cathode catalyst in platinum-based polymer electrolyte fuel cells is a key technical challenge. Here, we synthesize a high surface area meso-structured Pt thin film that exhibits higher specific activity for the oxygen reduction reaction (ORR) than commercial carbon-supported Pt nanoparticles (Pt/C). An accelerated stability test demonstrates that the meso-structured Pt thin film also displays significantly enhanced stability as compared to the commercial Pt/C catalyst. Our study reveals the origin of the high turnover frequency (TOF), and excellent durability is attributed to the meso-structure, which yields a morphology with fewer undercoordinated Pt sites than Pt/C nanoparticles, a key difference with substantial impact to the surface chemistry. The improved catalyst activity and stability could enable the development of a high-performance gas diffusion electrode that is resistant to corrosion even under the harsh conditions of start-up, shut-down, and/or hydrogen starvation.

Efficient organic light-emitting diodes with phosphorescent platinum complexes containing N∧C∧N-coordinating tridentate ligand

Abstract: We describe the phosphorescent characteristics of two platinum complexes containing an N∧C∧N-coordinating tridentate ligand: platinum(II) 3,5-di(2-pyridyl)toluene chloride [Pt(dpt)Cl] and a newly synthesized platinum(II) 3,5-di(2-pyridyl)toluene phenoxide [Pt(dpt)(oph)], together with the performance of organic light-emitting diodes (OLEDs) prepared with these complexes as phosphors. Films containing each one of the complexes in a 4,4’-N,N’-dicalbazolylbiphenyl (CBP) host showed highly efficient photoluminescence. The fabricated OLEDs exhibited high efficiencies; the maximum external quantum efficiency of the device with Pt(dpt)(oph) phosphor after correction of angular dependence of emission was found to be 16.5%. The luminance half decay time of the Pt(dpt)(oph) device under a constant-current operation was considerably longer than that of the Pt(dpt)Cl device.

Performance of Proton Exchange Membrane Fuel Cell Electrodes Prepared by Direct Deposition of Ultrathin Platinum on the Membrane Surface

Abstract: Proton exchange membrane fuel cell (PEMFC) electrodes were fabricated using a plasma-sputtering technique that deposits platinum directly on the surface of the Nafion electrolyte. This thin catalyst layer showed remarkable improvement in utilization efficiency, defined as the utilizable portion of the total deposited catalyst. This efficiency, equivalent to 0.043 mg Pt cm -2 loading of platinum, is about ten times higher than that of the electrodes produced by conventional methods. Application of carbon/Nafion ink on the bare Nafion surface prior to the initial sputtering, and repetition of the sputtering followed by the application of the ink on the treated surface after each sputtering, greatly enhanced the utilization efficiency of the loaded platinum.

Method for producing an unsaturated carboxylic acid

Abstract: A method for producing an unsaturated carboxylic acid, which comprises subjecting an alkane to a vapor phase catalytic oxidation reaction in the presence of a catalyst containing a mixed metal oxide comprising, as essential components, Mo, V, Te, O and X wherein X is at least one element selected from the group consisting of niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium and cerium, wherein the proportions of the respective essential components, based on the total amount of the essential components exclusive of oxygen, satisfy the following formulas: 0.25