scholarly journals Anisotropy of Pt nanoparticles on carbon- and oxide-support and their structural response to electrochemical oxidation probed by in situ techniques

2020 ◽  
Vol 22 (39) ◽  
pp. 22260-22270
Author(s):  
Henrike Schmies ◽  
Arno Bergmann ◽  
Elisabeth Hornberger ◽  
Jakub Drnec ◽  
Guanxiong Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Electrochemical Oxidation ◽  
Structural Response ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
Oxide Support ◽  
Pt Dissolution

Investigations on the (electronic) structure of carbon- and oxide-supported Pt nanoparticles during electrochemical oxidation via in situ X-ray diffraction, absorption spectroscopy and the Pt dissolution rate by in situ mass spectrometry.

In Situ X-Ray Diffraction and In Situ X-Ray Absorption Spectroscopy for Investigation of Intercalation Batteries: Application to the Alkaline H+/γ-MnO2 system.

1990 ◽  
Vol 210 ◽  
Author(s):  
C. Lévy-Clèment ◽  
C. Mondoloni ◽  
C. Godart ◽  
R. Cortès
Keyword(s):  
Charge Transfer ◽  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Alkaline Batteries ◽  
X Ray ◽  
In Situ Techniques ◽  
X Ray Absorption

AbstractThis paper presents applications of in situ X-ray diffraction and absorption techniques to the study of H+/MnO2 alkaline batteries. The two complementary in situ techniques are described. Investigation of the electrochemical insertion and deinsertion of H+ has been made through its influence on the evolution of the crystallographic structure of γ-MnO2, while investigation of the transfer of e has been undertaken through the variation of the oxidation state of the manganese during the discharging and charging process of a battery. New insights in the understanding of the mechanisms of proton insertion and charge transfer into γ-MnO2 are discussed.

A dispenser–reactor apparatus applied forin situXAS monitoring of Pt nanoparticle formation

2015 ◽  
Vol 22 (3) ◽  
pp. 736-744 ◽  
Author(s):  
Jocenir Boita ◽  
Marcus Vinicius Castegnaro ◽  
Maria do Carmo Martins Alves ◽  
Jonder Morais
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Pt Nanoparticles ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Two Stages ◽  
X Ray Absorption

In situtime-resolved X-ray absorption spectroscopy (XAS) measurements collected at the PtL3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser–reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.

scholarly journals In-situ X-ray techniques for non-noble electrocatalysts

2020 ◽  
Vol 92 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Sung-Fu Hung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Mechanism ◽  
Structural Evolution ◽  
Reduction Reaction ◽  
High Price ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
State Variation

AbstractElectrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.

Thermal expansion coefficient of carbon-supported Pt nanoparticles: In-situ X-ray diffraction study

2017 ◽  
Vol 254 (5) ◽  
pp. 1600695 ◽  
Author(s):  
I. N. Leontyev ◽  
A. A. Kulbakov ◽  
M. Allix ◽  
A. Rakhmatullin ◽  
A. B. Kuriganova ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Diffraction Study ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst

2013 ◽  
Vol 78 (11) ◽  
pp. 1703-1716 ◽  
Author(s):  
Mila Krstajic ◽  
Maja Obradovic ◽  
Biljana Babic ◽  
Velimir Radmilovic ◽  
Uros Lacnjevac ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Methanol Oxidation ◽  
Pt Nanoparticles ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxidation Of Methanol ◽  
Potentiodynamic Polarization Curves ◽  
Transmission Electron

The Ru-doped SnO2 powder, (RuxSn1-x)O2, with the Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass% loading). The (RuxSn1-x)O2 support and Pt/(RuxSn1-x)O2 catalyst were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM). (RuxSn1-x)O2 was found to be two-phase material consisting of probably solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-x)O2 indicated good conductivity of the sup-port and displayed usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-x)O2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-x)O2 starts at less positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of Pt/(RuxSn1-x)O2 catalyst compared to PtRu/C, but also a greater loss in the current density over time. Potentiodynamic stability test of the catalysts revealed that deactivation of the Pt/(RuxSn1-x)O2 and Pt/C was primarily caused by the poisoning of Pt surface by the methanol oxidation residues, which mostly occurred during the first potential cycle. In the case of PtRu/C the poisoning of the surface was minor and deactivation was caused by the PtRu surface area loss.

scholarly journals Using in-situ techniques to probe high-temperature reactions: thermochemical cycles for the production of synthetic fuels from CO2 and water

2012 ◽  
Vol 27 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Eric N. Coker ◽  
Mark A. Rodriguez ◽  
Andrea Ambrosini ◽  
James E. Miller ◽  
Ellen B. Stechel
Keyword(s):  
Iron Oxide ◽  
Inert Atmosphere ◽  
Solar Thermal Energy ◽  
X Ray Diffraction ◽  
Synthetic Fuels ◽  
Thermochemical Cycles ◽  
X Ray ◽  
In Situ Techniques ◽  
Dissolved Iron

Ferrites are promising materials for enabling solar-thermochemical cycles. Such cycles utilize solar-thermal energy to reduce the metal oxide, which is then re-oxidized by H2O or CO2, producing H2 or CO, respectively. Mixing ferrites with zirconia or yttria-stabilized zirconia (YSZ) greatly improves their cyclabilities. In order to understand this system, we have studied the behavior of iron oxide/8YSZ (8 mol-% Y2O3 in ZrO2) using in situ X-ray diffraction and thermogravimetric analyses at temperatures up to 1500 °C and under controlled atmosphere. The solubility of iron oxide in 8YSZ measured by XRD at room temperature was 9.4 mol-% Fe. The solubility increased to at least 10.4 mol-% Fe when heated between 800 and 1000 °C under inert atmosphere. Furthermore iron was found to migrate in and out of the 8YSZ phase as the temperature and oxidation state of the iron changed. In samples containing >9.4 mol-% Fe, stepwise heating to 1400 °C under helium caused reduction of Fe2O3 to Fe3O4 to FeO. Exposure of the FeO-containing material to CO2 at 1100 °C re-oxidized FeO to Fe3O4 with evolution of CO. Thermogravimetric analysis during thermochemical cycling of materials with a range of iron contents showed that samples with mostly dissolved iron utilized a greater proportion of the iron atoms present than did samples possessing a greater fraction of un-dissolved iron oxides.

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