Thermal Stability and Catalytic Activity of the MnOx–CeO2 and the MnOx–ZrO2–CeO2 Highly Dispersed Materials in the Carbon Monoxide Oxidation Reaction

2021 ◽  
Vol 12 (2) ◽  
pp. 468-476
Author(s):  
E. Yu. Liberman ◽  
B. S. Kleusov ◽  
A. V. Naumkin ◽  
I. V. Zagaynov ◽  
T. V. Konkova ◽  
...  
2020 ◽  
pp. 75-87
Author(s):  
E. Yu. Liberman ◽  
◽  
B. S. Kleusov ◽  
A. V. Naumkin ◽  
I. V. Zagaynov ◽  
...  

Highly dispersed catalysts MnOx-CeO2 and MnOx – ZrO2 – CeO2 were synthesized for the oxidation of carbon monoxide. Using XRD and XRF methods, the formation of Mn – Ce – O and Mn – Zr – Ce – O solid solutions, as well as the presence of Mn2O3 and Mn3O4, was established. The specific surface area of the synthesized materials is 121 and 155 m2/g, respectively, with a particle size of 8-10 nm. Deconvolution of XPS spectra was carried out, the relative content of ionic forms of Mn, lattice oxygen Оα and high-energy forms Оβ was determined. When studying the thermal stability of the catalysts, it was found that bicomponent systems have low thermal stability, which leads to an enlargement of particle sizes to 32 nm, a decrease in the specific surface to 29 m2/g, and, as a consequence, to a decrease in catalytic activity. While for MnOx – ZrO2 – CeO2, less significant changes are observed: the particle size is 27 nm, the specific surface is 43 m2/g, while the catalytic activity is higher than for MnOx – CeO2. The study of the state of the components of the surface layer of the catalysts after isothermal exposure allowed to ascertain changes in the content of the ionic forms Mn, Oα, and Oβ. Based on the studies, it can be concluded that it is advisable to dope the bicomponent systems MnOx – CeO2 with Zr4+ ions. The resulting solid solution ZrO2 – MnOx – CeO2 is more stable under the influence of high temperatures.


2019 ◽  
Vol 92 (5) ◽  
pp. 655-660 ◽  
Author(s):  
E. Yu. Liberman ◽  
E. S. Pod”el’nikova ◽  
E. A. Simakina ◽  
T. V. Kon’kova ◽  
B. S. Kleusov

Author(s):  
Tomotaka Abe ◽  
Ken’ichi Hiratsuka ◽  
Czesław Kajdas

Oxidation reaction of methane is one of the most fundamental reactions in organic chemistry. This reaction is enhanced by silver catalyst [1]. In this study, we confirmed that the catalytic activity of silver is enhanced more by the friction. This effect is called tribocatalysis. In previous studies about tribocatalysis, we have shown that the oxidation reactions of hydrogen [2], carbon monoxide [3] and ethylene were promoted by the friction. According to NIRAM (negative-ion-radical action mechanism) approach, exo-electron emission triggers the promotion of chemical reactions [4]. Insulator such as aluminum oxide, when it is worn, emits larger number of negative particles including electrons compared with metals [5]. Therefore we expected that the friction of aluminum oxide promotes tribochemical reactions more than metals.


2009 ◽  
Vol 133 (3-4) ◽  
pp. 354-361 ◽  
Author(s):  
Guoqian Chen ◽  
Ying Zheng ◽  
Guohui Cai ◽  
Yong Zheng ◽  
Yihong Xiao ◽  
...  

2015 ◽  
Vol 7 (6) ◽  
pp. 2049-2065
Author(s):  
Débora M. Bezerra ◽  
João Elias F. S. Rodrigues ◽  
Adeilton P. Maciel

2020 ◽  
Vol 14 (2) ◽  
pp. 266-269 ◽  
Author(s):  
M. V. Grishin ◽  
A. K. Gatin ◽  
V. G. Slutskii ◽  
A. S. Fedotov ◽  
V. A. Kharitonov ◽  
...  

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