Stable Stoichiometry of Gas-Phase Manganese Oxide Cluster Ions Revealed by Temperature-Programmed Desorption

2015 ◽  
Vol 119 (31) ◽  
pp. 8433-8442 ◽  
Author(s):  
Kohei Koyama ◽  
Satoshi Kudoh ◽  
Ken Miyajima ◽  
Fumitaka Mafuné
Author(s):  
Francesca Varsano ◽  
Mariangela Bellusci ◽  
Carlo Alvani ◽  
Aurelio La Barbera ◽  
Franco Padella ◽  
...  

A novel system composed by an aqueous slurry prepared by MnO and NaOH mixture was tested for the hydrogen production in the sodium manganese oxide thermochemical cycle. The hydrogen evolution occurs at lower temperature than conventional mixtures utilized in the cycle. Experiments performed in a Temperature Programmed Desorption/Reaction apparatus (TPD/TPR) have evidenced hydrogen production around 500°C. The hydrolysis step of α-NaMnO2 has been studied and the importance to conduct hydrolysis reaction under inert gas is discussed. A manganese disproportion mechanism is hypothesized to explain the appearance of manganese (II) and manganese (IV) containing phases.


2008 ◽  
Vol 112 (21) ◽  
pp. 4732-4735 ◽  
Author(s):  
Grant E. Johnson ◽  
Eric C. Tyo ◽  
A. W. Castleman

1998 ◽  
Vol 17 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Elena F. Fialko ◽  
Andrey V. Kikhtenko ◽  
Vladimir B. Goncharov

2018 ◽  
Vol 91 (10) ◽  
pp. 1530-1536 ◽  
Author(s):  
Daigo Masuzaki ◽  
Yuma Takehashi ◽  
Fumitaka Mafuné

2004 ◽  
Vol 49 (4) ◽  
pp. 141-145 ◽  
Author(s):  
S. Preis ◽  
J.L. Falconer

Methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) were oxidized in the gas phase by photocatalytic oxidation (PCO). Transient PCO was carried out at room temperature on TiO2 (Degussa P25), 0.2% Pt-TiO2, and 2% Pt-TiO2 catalysts. Surface-adsorbed reaction by-products were characterized by temperature-programmed desorption (TPD) and oxidation (TPO). Continuous flow PCO was also carried out at 373 K on TiO2. Acetone, H2O, and CO2 were the gas-phase products for PCO of TBA and MTBE, and formic acid was adsorbed on the TiO2 surface. Temperature-programmed desorption of TBA and MTBE formed 2-methyl-1-propene, water (TBA), and methanol (MTBE). During continuous-flow PCO, acetone desorbed in molar amounts equal to the amount of decomposed TBA and MTBE. The Pt/TiO2 catalysts had higher rates of complete oxidation during PCO and TPO. Injection of water during transient PCO increased the rates of oxidation of adsorbed TBA, formic acid, and acetone. Photocatalytic oxidation of TBA proceeded faster in humid air than dry air, but MTBE oxidation was less sensitive to humidity. The TiO2 catalyst was stable for MTBE, TBA, and acetone PCO at 373 K. The PCO at low conversions followed the Langmuir-Hinshelwood model.


2001 ◽  
Vol 114 (2) ◽  
pp. 798 ◽  
Author(s):  
R. C. Bell ◽  
K. A. Zemski ◽  
D. R. Justes ◽  
A. W. Castleman

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