Dimethyl Ether Steam Reforming over Cu–Zn–Pd/CeO2–ZrO2 Catalytic Monoliths. The Role of Cu Species on Catalyst Stability

2011 ◽  
Vol 115 (23) ◽  
pp. 11624-11632 ◽  
Author(s):  
Cristian Ledesma ◽  
Jordi Llorca
Author(s):  
Jing-Hong Lian ◽  
Hongyi Tan ◽  
Changqing Guo ◽  
Li-sha Shen ◽  
Zhuo-Xin Lu ◽  
...  

The inactivation of molybdenum carbide catalyst by water oxidation is a significant problem in steam reforming of dimethyl ether (SRD) reaction. In this work, the catalytic performance and stability of...


2012 ◽  
Vol 187 ◽  
pp. 299-305 ◽  
Author(s):  
Jing Li ◽  
Qi-Jian Zhang ◽  
Xu Long ◽  
Ping Qi ◽  
Zhao-Tie Liu ◽  
...  

2020 ◽  
Vol 500 (3) ◽  
pp. 3414-3424
Author(s):  
Alec Paulive ◽  
Christopher N Shingledecker ◽  
Eric Herbst

ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.


2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
Abdul-Majeed Azad ◽  
Desikan Sundararajan

Clean power source utilizing vast logistic fuel reserves (jet fuels, diesel, and coal) would be the main driver in the 21st century for high efficiency. Fuel processors are required to convert these fuels into hydrogen-rich reformate for extended periods in the presence of sulfur, and deliver hydrogen with little or no sulfur to the fuel cell stack. However, the jet and other logistic fuels are invariably sulfur-laden. Sulfur poisons and deactivates the reforming catalyst and therefore, to facilitate continuous uninterrupted operation of logistic fuel processors, robust sulfur-tolerant catalysts ought to be developed. New noble metal-supported ceria-based sulfur-tolerant nanocatalysts were developed and thoroughly characterized. In this paper, the performance of single metal-supported catalysts in the steam-reforming of kerosene, with 260 ppm sulfur is highlighted. It was found that ruthenium-based formulation provided an excellent balance between hydrogen production and stability towards sulfur, while palladium-based catalyst exhibited rapid and steady deactivation due to the highest propensity to sulfur poisoning. The rhodium supported system was found to be most attractive in terms of high hydrogen yield and long-term stability. A mechanistic correlation between the role of the nature of the precious metal and the support for generating clean desulfurized -rich reformate is discussed.


2021 ◽  
Vol 132 (2) ◽  
pp. 907-919
Author(s):  
O. Shtyka ◽  
Z. Dimitrova ◽  
R. Ciesielski ◽  
A. Kedziora ◽  
G. Mitukiewicz ◽  
...  

AbstractEthanol steam reforming was studied over Ni supported catalysts. The effects of support (Al2O3, Al2O3–ZnO, and Al2O3–CeO2), metal loading, catalyst activation method, and steam-to-ethanol molar feed ratio were investigated. The properties of catalysts were studied by N2 physisorption, TPD-CO2, X-ray diffraction, and temperature programmed reduction. After activity tests, the catalysts were analyzed by TOC analysis. The catalytic activity measurements showed that the addition either of ZnO SSor CeO2 to alumina enhances both ethanol conversion and promotes selectivity towards hydrogen formation. The same effects were observed for catalysts with higher metal loadings. High process temperature and high water-to-ethanol ratio were found to be beneficial for hydrogen production. An extended catalyst stability tests showed no loss of activity over 50 h on reaction stream. The TOC analysis of spent catalysts revealed only insignificant amounts of carbon deposit.


2006 ◽  
Vol 304 ◽  
pp. 40-48 ◽  
Author(s):  
Kajornsak Faungnawakij ◽  
Yohei Tanaka ◽  
Naohiro Shimoda ◽  
Tetsuya Fukunaga ◽  
Shunichiro Kawashima ◽  
...  

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