Redox Dynamics of Pd Supported on CeO2–ZrO2 during Oxygen Storage/Release Cycles Analyzed by Time-Resolved in Situ Reflectance Spectroscopy

2018 ◽  
Vol 122 (49) ◽  
pp. 28173-28181 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Riichiro Kakei ◽  
Ayumi Fujiwara ◽  
Yuki Uchida ◽  
Masato Machida
Keyword(s):  
Reflectance Spectroscopy ◽  
Oxygen Storage ◽  
Time Resolved ◽  
Redox Dynamics

In Situ Time-Resolved Redox Dynamics of Pd Catalysts Under Oscillating A/F Conditions

2018 ◽  
Vol 62 (1-4) ◽  
pp. 345-350 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Riichiro Kakei ◽  
Ayumi Fujiwara ◽  
Atsuko Tomita ◽  
Takeshi Miki ◽  
...  
Keyword(s):  
Pd Catalysts ◽  
Time Resolved ◽  
Redox Dynamics

Redox Dynamics of Rh Supported on ZrP2O7 and ZrO2 Analyzed by Time-Resolved In Situ Optical Spectroscopy

2017 ◽  
Vol 121 (33) ◽  
pp. 17982-17989 ◽  
Author(s):  
Haris Puspito Buwono ◽  
Masahiro Yamamoto ◽  
Riichiro Kakei ◽  
Satoshi Hinokuma ◽  
Hiroshi Yoshida ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
Time Resolved ◽  
Redox Dynamics

Exciton dynamics in thick GaN MOVPE epilayers deposited on sapphire.

1997 ◽  
Vol 2 ◽  
Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
J. Camassel ◽  
B. Beaumont ◽  
Pierre Gibart
Keyword(s):  
Layer Thickness ◽  
Buffer Layers ◽  
Rate Equations ◽  
Time Resolved ◽  
Versus Layer ◽  
Level Model ◽  
Shallow Impurities ◽  
Aln Buffer ◽  
Time Resolved Photoluminescence

Time-resolved photoluminescence spectra have been recorded on three GaN epitaxial layers of thickness 2.5 μm, 7 μm and 16 μm, at various temperatures ranging from 8K to 300K. The layers were deposited by MOVPE on (0001) sapphire substrates with standard AlN buffer layers. To achieve good homogeneities, the growth was in-situ monitored by laser reflectometry. All GaN layers showed sharp excitonic peaks in cw PL and three excitonic contributions were seen by reflectivity. The recombination dynamics of excitons depends strongly upon the layer thickness. For the thinnest layer, exponential decays with τ ~ 35 ps have been measured for both XA and XB free excitons. For the thickest layer, the decay becomes biexponential with τ1 ~ 80 ps and τ2 ~ 250 ps. These values are preserved up to room temperature. By solving coupled rate equations in a four-level model, this evolution is interpreted in terms of the reduction of density of both shallow impurities and deep traps, versus layer thickness, roughly following a L−1 law.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

Sign in / Sign up

Export Citation Format

Share Document