Surface active sites of vanadium pentoxide-tin dioxide catalysts

1990 ◽  
Vol 94 (15) ◽  
pp. 5900-5908 ◽  
Author(s):  
Fumio. Okada ◽  
Atsushi. Satsuma ◽  
Akio. Furuta ◽  
Akira. Miyamoto ◽  
Tadashi. Hattori ◽  
...  
1989 ◽  
Vol 93 (4) ◽  
pp. 1484-1490 ◽  
Author(s):  
Atsushi Satsuma ◽  
Atsushi Hattori ◽  
Koichi Mizutani ◽  
Akio Furuta ◽  
Akira Miyamoto ◽  
...  

1988 ◽  
Vol 92 (21) ◽  
pp. 6052-6058 ◽  
Author(s):  
Atsushi Satsuma ◽  
Atsushi Hattori ◽  
Koichi Mizutani ◽  
Akio Furuta ◽  
Akira Miyamoto ◽  
...  

2014 ◽  
Vol 605 ◽  
pp. 227-230 ◽  
Author(s):  
Artem Marikutsa ◽  
Marina Rumyantseva ◽  
Alexander Gaskov

The possibility to discriminate two reducing gases CO and NH3 in their mixture by semiconductor gas sensors based on modified nanocrystalline tin dioxide was demonstrated. The selectivity was achieved by the optimization of SnO2 microstructure, surface modifier and operating temperature. Introducing catalytic clusters of palladium or ruthenium oxides increased tin dioxide sensitivity to CO at low temperature and to ammonia at raised temperature, respectively. Cross-sensing tests verified that SnO2/RuO2 sensors are selective to NH3 in comparison with CO, while SnO2/PdO displayed a complex behaviour in the presence of both gases. Possible sensor signal formation routes are discussed regarding the modifiers catalytic action and their distinctive influence on surface active sites.


1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.


Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...


2020 ◽  
Vol 9 (1) ◽  
pp. 191-202
Author(s):  
Jian Wang ◽  
Chao Zhu ◽  
Baowei Li ◽  
Zhijun Gong ◽  
Zhaolei Meng ◽  
...  

AbstractTo research the roles of rare earth minerals in denitrification via the NH3-SCR, a mixture was made by certain ratio of rare earth concentrates and rare earth tailings, then treated by microwave roasting, and acids and bases to form a denitrification catalyst. The mineral phase structure and surface morphology of the catalyst were characterized by XRD, BET, SEM and EDS. The surface properties of the catalyst were tested by TPD and XPS methods, and the denitrification activity of the catalyst was evaluated in a denitrification reactor. The results showed that the denitrification efficiency increased up to 82% with complete processing. XRD, BET, SEM, and EDS spectrum analysis stated that the treated minerals contained cerium oxides and Fe−Ce composite oxides. The surface of the modified minerals became rough and porous, the surface area increased, and the surface-active sites were exposed. The results of NH3-TPD and NO-TPD showed that the catalyst surface could gradually adsorb more NH3 and NO after each step. XPS analysis indicated that there were more Ce3+, Fe2+, and lattice oxygen in rare earth minerals catalyst after each treatment step.


2014 ◽  
Vol 2 (18) ◽  
pp. 6296-6300 ◽  
Author(s):  
Yuan Peng ◽  
Zhongnan Guo ◽  
Jingjing Yang ◽  
Da Wang ◽  
Wenxia Yuan

Fine-tuning surface activation of the micro-SiC catalyst via hybridizing a suitable amount of CdS to obtain effective surface active sites.


Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21671-21680 ◽  
Author(s):  
Wenbin Li ◽  
Jianfeng Huang ◽  
Liangliang Feng ◽  
Liyun Cao ◽  
Shuwei He

The decreasing crystallinity of VS4 microspheres greatly increases the surface active sites, and then promotes the pseudocapacitive behavior, and finally leads to the high capacity, long cycling life and high rate capability.


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