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.

Electrocatalytic Oxidation of Formic Acid at an Ordered Intermetallic PtBi Surface

Abstract: The electrocatalytic oxidation of formic acid at a PtBi ordered intermetallic electrode surface has been investigated using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and differential electrochemical mass spectrometry (DEMS). The results are compared to those at a polycrystalline platinum electrode surface. The PtBi electrode exhibits superior properties when compared to polycrystalline platinum in terms of oxidation onset potential, current density, and a much diminished poisoning effect by CO. Using the RDE technique, a value of 1.4 x 10(-4) cm s-1 was obtained for the heterogeneous charge transfer rate constant. The PtBi surface did not appear to be poisoned when exposed to a CO saturated solution for periods exceeding 0.5 h. The results for PtBi are discussed within the framework of the dual-path mechanism for the electrocatalytic oxidation of formic acid, which involves formation of a reactive intermediate and a poisoning pathway.

Platinum-Based Catalysts on Various Carbon Supports and Conducting Polymers for Direct Methanol Fuel Cell Applications: a Review

Abstract: Platinum (Pt)-based nanoparticle metals have received a substantial amount of attention and are the most popular catalysts for direct methanol fuel cell (DMFC). However, the high cost of Pt catalysts, slow kinetic oxidation, and the formation of CO intermediate molecules during the methanol oxidation reaction (MOR) are major challenges associate with single-metal Pt catalysts. Recent studies are focusing on using either Pt alloys, such as Fe, Ni, Co, Rh, Ru, Co, and Sn metals, or carbon support materials to enhance the catalytic performance of Pt. In recent years, Pt and Pt alloy catalysts supported on great potential of carbon materials such as MWCNT, CNF, CNT, CNC, CMS, CNT, CB, and graphene have received remarkable interests due to their significant properties that can contribute to the excellent MOR and DMFC performance. This review paper summaries the development of the above alloys and support materials related to reduce the usage of Pt, improve stability, and better electrocatalytic performance of Pt in DMFC. Finally, discussion of each catalyst and support in terms of morphology, electrocatalytic activity, structural characteristics, and its fuel cell performance are presented.

Relationship between the area of L2,3 x‐ray absorption edge resonances and the d orbital occupancy in compounds of platinum and iridium

Abstract: The relationship between the intensity of the L 2 and L 3 x‐ray absorption threshold resonances and d orbital occupancy has been investigated for a series of compounds of platinum and iridium and the pure metals, using Xα‐SW molecular orbital calculations to obtain the unoccupied d orbital states. The change in d orbital occupancy caused by formation of the core hole was found to be fairly constant in different compounds and the pure metal. The difference between the d orbital occupancy in platinum metal and the d orbital occupancy in a given platinum compound agrees well with the calculated effective charge on the platinum atom in the compound. The areas of the threshold resonance lines were obtained by a deconvolution of the absorption edge into a Lorentzian component and an underlying ’’step’’ representing the onset of absorption to continuum states. For a series of platinum compounds, a linear relationship was obtained between the unoccupied d orbital states calculated in the core hole potential, and the sum of the areas of the L 2 and L 3 threshold resonance lines (corrected for the different degeneracies of the initial state). However, this relationship could not be applied to IrO2 because of the absence of transitions to empty d states at the top of the valence band.