Evolution of Pt Nanoclusters Morphology on PEMFC Electrode due to Methanol Oxidation Reaction Studied by Electron Microscopy and Synchrotron Grazing Incidence X-Ray Diffraction

2006 ◽  
pp. 181-186
Author(s):  
Marco Alvisi ◽  
Giovanna Galtieri ◽  
L. Giorgi ◽  
Emanuele Serra ◽  
Tiziana Di Luccio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Grazing Incidence ◽  
Methanol Oxidation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pt Nanoclusters

Evolution of Pt Nanoclusters Morphology on PEMFC Electrode due to Methanol Oxidation Reaction Studied by Electron Microscopy and Synchrotron Grazing Incidence X-Ray Diffraction

2006 ◽  
Vol 51 ◽  
pp. 181-186
Author(s):  
Marco Alvisi ◽  
Giovanna Galtieri ◽  
L. Giorgi ◽  
Emanuele Serra ◽  
Tiziana Di Luccio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fuel Cells ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Catalyst Layer ◽  
Grazing Incidence ◽  
Pt Catalyst ◽  
Methanol Oxidation Reaction ◽  
X Ray Diffraction ◽  
X Ray

The proton exchange membrane fuel cells (PEMFC) have been developed mainly as a power source for vehicles, power generation and consumer electronics since they combine high energy conversion efficiency at relatively low temperatures without pollutants emission in the environment. An electrode for a PEMFC is a layered structure composed by a catalyst layer deposited on a porous carbon substrate. The substrate is usually covered by a diffusion layer that enhances the gas and water flow. Platinum nanoparticles supported by carbon microparticles are commonly employed as catalyst layer. In this work an extreme ultra-low loading of Pt catalyst (< 0.02 mg/cm2) has been deposited by magnetron sputtering on gas diffusion electrodes, with different carbon supports (Vulcan and SuperP), in order to enhance the activity of PEM fuel cells. The morphology (shape and grain size) and microstructure have been studied combining field emission scanning electron microscopy (FEG-SEM), grazing incidence synchrotron x-ray diffraction (GIXRD) and x-ray photoelectron spectroscopy (XPS). The results presented here concern the evolution of the cluster size and shape after the ageing, induced by cyclic voltammetry for methanol oxidation reaction.

Synthesis of NiO/TiO2 sub-microrods as catalyst for methanol oxidation reaction

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040002
Author(s):  
Xiaoyu Yue ◽  
Yixuan Wang ◽  
Ting Zhang ◽  
Wei Gao
Keyword(s):  
Electron Microscopy ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Direct Methanol Fuel Cells ◽  
Methanol Oxidation Reaction ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Potential Applications ◽  
Direct Methanol ◽  
Limited Oxygen

[Formula: see text] sub-microrods have been synthesized via a simple two-step route. First, the precursors were prepared by a facile ethylene glycol-mediated method; then, [Formula: see text] sub-microrods were obtained by a limited-oxygen atmosphere deriving from the decomposition of urea at [Formula: see text]C for 3 h in air. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The obtained [Formula: see text] sub-microrods exhibit cubic NiO structure with high crystallinity and anatase [Formula: see text]. Both SEM and TEM show the typical sub-microrods with lengths of [Formula: see text] nm and diameters of [Formula: see text] nm. The uniform sub-microrods have great electrocatalytic performance for methanol oxidation reaction in alkaline solution. This material may have potential applications in direct methanol fuel cells.

Carbon Supported Pt+Os Catalysts for Methanol Oxidation

2002 ◽  
Vol 57 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Gülsün Gökağaç ◽  
Brendan J. Kennedy
Keyword(s):  
Methanol Oxidation ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Carbon Support ◽  
Methanol Oxidation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Metal Metal ◽  
Metal Support

11% Pt/C, 10% Pt + 1%Os/C, 9% Pt + 2%Os/C, 8% Pt + 3%Os/C, 7% Pt + 4%Os/C, 6% Pt + 5%Os/C and 5%Pt + 6% Os/C catalysts have been prepared for methanol oxidation reaction. Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry have been used to understand the nature of the species present in these catalysts. 7% Pt + 4% Os/C was the most active catalyst, while 8% Pt + 3% Os/C was the least active one. It is found that the metal particle size and distribution on the carbon support, the surface composition and the oxidation states of the metal particles, the metal-metal and metal support interactions are important parameters to define the activity of the catalyst.

Supramolecular organization of a H-bonded perylene bisimide organogelator determined by transmission electron microscopy, grazing incidence X-ray diffraction and polarized infra-red spectroscopy

2017 ◽  
Vol 19 (48) ◽  
pp. 32514-32525 ◽  
Author(s):  
Alexandru Sarbu ◽  
Patrick Hermet ◽  
David Maurin ◽  
David Djurado ◽  
Laure Biniek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grazing Incidence ◽  
Supramolecular Organization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Perylene Bisimide ◽  
Transmission Electron ◽  
Infra Red ◽  
Polarized Ftir

Polarized FTIR and TEM helps determine the supramolecular organization of PBI gelators.

Orientation Relationships between BCC Deposits and FCC Substrates

1987 ◽  
Vol 94 ◽  
Author(s):  
David A. Smith ◽  
Armin Segmüller ◽  
A. R. Taranko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
Bcc Metals ◽  
Transmission Electron ◽  
Deposited Films

ABSTRACTOriented deposits are commonplace in vapor deposited films. The origins of this behavior are not always clear. Various bcc metals (Fe, Nb, Mo, Ta, Cr) have been deposited onto single crystal fcc substrates (Au, Ni, MgO, Si, NaCI) which were selected with the intention of varying the character of the substrate-deposit interaction. The resulting structures have been characterized by transmission electron microscopy and grazing incidence x-ray diffraction. The observed variants of the cube-cube and Nishiyama-Wassermann orientation relationship can be understood in terms of minimization of misfit except when there is a weak interaction between substrate and deposit.

Study of Germanium Epitaxial Recrystallization on Bulk-Si Substrates

2010 ◽  
Vol 1252 ◽  
Author(s):  
Byron Ho ◽  
Reinaldo Vega ◽  
Tsu-Jae King-Liu
Keyword(s):  
Electron Microscopy ◽  
Diffusion Theory ◽  
Grazing Incidence ◽  
Quasi Equilibrium ◽  
X Ray Diffraction ◽  
Rapid Thermal Anneal ◽  
Simple Diffusion ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

AbstractLPCVD Ge films are deposited onto bulk Si substrates and subjected to either a rapid thermal anneal (RTA) or furnace anneal (FA) at a temperature that is higher than the melting point of Ge in an attempt to induce epitaxial recrystallization. Spiking into the Si and voids in the Ge film are observed after the anneal. This is attributed to defect-assisted Ge diffusion into the Si substrate caused by strain at the Ge-Si interface. Simple diffusion theory using published diffusivity values predicts diffusion depths similar to the spiking depths observed by scanning electron microscopy and transmission electron microscopy. Approaches to reduce the strain at the interface are explored. It is found that the quasi-equilibrium nature of FA reduces spiking and that there is an area dependence. Grazing-incidence x-ray diffraction analysis suggests that this technique for epitaxial recrystallization does not result in single-crystalline Ge.

scholarly journals Methanol Oxidation on Graphenic-Supported Platinum Catalysts

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 16-31 ◽  
Author(s):  
Gladys Arteaga ◽  
Luis M. Rivera-Gavidia ◽  
Sthephanie J. Martínez ◽  
Rubén Rizo ◽  
Elena Pastor ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Methanol Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Reaction ◽  
Catalyst Support ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Methanol Oxidation Reaction ◽  
X Ray ◽  
Supported Platinum Catalysts

Graphene oxide (GO), reduced graphene oxide by thermal treatment (rGO-TT), nitrogen-modified rGO (N-rGO), and carbon Vulcan were synthesized and employed in the current work as catalyst support for Pt nanoparticles, to study their properties and impact toward the methanol oxidation reaction (MOR) in sulfuric acid medium. Several physicochemical techniques, such as X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), Raman, and elemental analysis were employed to characterize the novel materials, while potentiodynamic and potentiostatic methods were used to study catalytic performance toward the methanol oxidation reaction in acidic medium. The main results indicate a high influence of the support on the surface electronic state of the catalyst, and consequently the catalytic performance toward the MOR is modified. Accordingly, Pt/N-rGO and Pt/rGO-TT show the lowest and the highest catalytic performance toward the MOR, respectively.

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