Pt-Sn/C as a possible methanol-tolerant cathode catalyst for DMFC

An effective method was developed for preparing highly dispersed nano-sized Pt–Sn/C electrocatalyst synthesised by a modified polyol reduction method. From XRD patterns, the Pt–Sn/C peaks shifted slightly to lower 2θ angles when compared with commercial Pt/C catalyst, suggesting that Sn formed alloy with Pt. Based on HR-TEM images, the Pt–Sn/C nanoparticles showed small particle sizes and well dispersed onto the carbon support with a narrow particle distribution. The methanol oxidation reaction on the as-prepared Pt–Sn/C catalyst appeared at lower currents (+7.08 mA at +480 mV vs. Ag/AgCl) compared to the commercial Pt/C (+8.25 mA at +480 mV vs. Ag/AgCl) suggesting that the Pt–Sn/C catalyst has ‘methanol tolerance capabilities’. Pt–Sn/C HA Slurry pH3 catalysts showed better activity towards the oxygen-reduction reaction (ORR) than commercial Pt/C which could be attributed to smaller particle sizes. In our study, the Pt–Sn/C catalyst appears to be a promising methanol-tolerant catalyst with activity towards the ORR in the DMFC.Web of Scienc

Systematic documentation and analysis of human genetic variation in hemoglobinopathies using the microattribution approach

We developed a series of interrelated locus-specific databases to store all published and unpublished genetic variation related to hemoglobinopathies and thalassemia and implemented microattribution to encourage submission of unpublished observations of genetic variation to these public repositories. A total of 1,941 unique genetic variants in 37 genes, encoding globins and other erythroid proteins, are currently documented in these databases, with reciprocal attribution of microcitations to data contributors. Our project provides the first example of implementing microattribution to incentivise submission of all known genetic variation in a defined system. It has demonstrably increased the reporting of human variants, leading to a comprehensive online resource for systematically describing human genetic variation in the globin genes and other genes contributing to hemoglobinopathies and thalassemias. The principles established here will serve as a model for other systems and for the analysis of other common and/or complex human genetic diseases

QDB: A new database of plasma chemistries and reactions

One of the most challenging and recurring problems when modeling plasmas is the lack of data on the key atomic and molecular reactions that drive plasma processes. Even when there are data for some reactions, complete and validated datasets of chemistries are rarely available. This hinders research on plasma processes and curbs development of industrial applications. The QDB project aims to address this problem by providing a platform for provision, exchange, and validation of chemistry datasets. A new data model developed for QDB is presented. QDB collates published data on both electron scattering and heavy-particle reactions. These data are formed into reaction sets, which are then validated against experimental data where possible. This process produces both complete chemistry sets and identifies key reactions that are currently unreported in the literature. Gaps in the datasets can be filled using established theoretical methods. Initial validated chemistry sets for SF 6 /CF 4 /O 2 and SF 6 /CF 4 /N 2 /H 2 are presented as examples

Synthesis and Characterization of Pt Catalysts on SnO2 Based Supports for Oxygen Reduction Reaction

The oxygen reduction reaction was studied at Pt nanocatalysts on two different tin oxide based supports, Sb-SnO2 and Ru-SnO2, in acid solution. Tin oxide based supports were synthesized by hydrazine reduction method. Physical characterization of the supports was performed by BET, X-ray diffraction and TEM techniques. SnO2 belonging peaks were detected in Sb-SnO2 powder, while Ru-SnO2 XRD diffraction patterns contained peaks of RuO2 and SnO2. The average crystallite sizes, determined by Scherrer equation, were 3 nm and 4 nm for Sb-SnO2 and Ru-SnO2, respectively. Pt catalysts on Sb-SnO2 and Ru-SnO2 supports were synthesized by borohydride reduction method. TEM analysis revealed homogeneous particle size distribution, with average particle size of 2.9 and 5.4 nm, for Sb-SnO2 and Ru-SnO2, respectively. Electrocatalytic activity and stability of these catalysts for oxygen reduction were studied by cyclic voltammetry and linear sweep voltammetry at rotating disk electrode (RDE). Pt catalysts on Sb and Ru doped SnO2 support exhibited catalytic activities comparable to Pt on commercial carbon based support. Stability tests were also performed. Determined small loss of electrochemical active surface area of the Pt catalyst on Sb doped tin oxide support, after repetitive cycling, indicated high stability and durability of this cathode for-prospective fuel cells application. (C) 2013 The Electrochemical Society. All rights reserved

Preparation and characterization TiOx-Pt/C catalyst for hydrogen oxidation reaction

The hydrogen oxidation reaction (HOR) was studied at the home made TiOx-Pt/C nanocatalysts in 0.5 mol dm(-3) HClO4 at 25 degrees C. Pt/C catalyst was first synthesized by modified ethylene glycol method (EG) on commercially used carbon support (Vulcan XC-72). Then TiOx-Pt/C catalyst was prepared by the polyole method followed by TiOx post-deposition. The synthesized catalyst was characterized by XRD, TEM and EDX techniques. It was found that Pt/C catalyst nanoparticles were homogenously distributed over carbon support with the mean particle size of about 2.4 nm. The quite similar, homogenous distribution and particle size were obtained for Pt/C doped by TiOx catalyst which was the confirmation that TiOx post-deposition did not lead to significant growth of the Pt nanoparticles. The electrochemically active surface area of the catalyst was determined by using the cyclic voltammetry technique. The kinetics of hydrogen oxidation was investigated by the linear sweep voltammetry technique at the rotating disc electrode (RDE). The kinetic equations used for the analysis were derived considering the reversible or irreversible nature of the kinetics of the HOR. It was found that the hydrogen oxidation reaction for an investigated catalyst proceeded as an electrochemically reversible reaction. The values determined for the kinetic parameters-Tafel slope of 28 mV dec(-1) and exchange current density about 0.4 mA cm(Pt)(-2) are in good agreement with usually reported values for a hydrogen oxidation reaction with platinum catalysts in acid solutions

Novel Pt catalyst on ruthenium doped TiO2 support for oxygen reduction reaction

Ruthenium doped titanium oxide support was synthesized. The support was characterized by BET (Brunauer, Emmett, Teller) and X-ray diffraction techniques (XRD). Determined specific surface area was 41 m(2) g(-1). XRD revealed presence mainly TiO2 anatase phase and some peaks belonging to rutile phase. No Ru compounds have been detected. Platinum based catalyst on this support was prepared by borohydride reduction method. The catalyst was characterized by scanning transmission electron microscopy (STEM, HAADF) and electron energy loss spectroscopy (EELS). Homogenous Pt particle distribution over the support, with average Pt nanoparticle diameter of 3 nm was found. This novel catalyst was tested for oxygen reduction in acid solution. It exhibited remarkable higher catalytic activity in comparison with Pt/C, as well as with Pt nanocatalysts at titanium oxide based supports, reported in literature. (C) 2013 Elsevier B.V. All rights reserved