A heterogeneous single Cu catalyst of Cu atoms confined in the spinel lattice of MgAl2O4 with good catalytic activity and stability for NO reduction by CO

2019 ◽  
Vol 7 (12) ◽  
pp. 7202-7212 ◽  
Author(s):  
Jichun Wu ◽  
Yuanzhi Li ◽  
Yi Yang ◽  
Qian Zhang ◽  
Li Yun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Temperature ◽  
No Reduction ◽  
Confinement Effect ◽  
No Reduction By Co ◽  
Spinel Lattice ◽  
Cu Catalyst ◽  
Good Catalytic Activity

A heterogeneous single Cu catalyst exhibits good catalytic activity and durability at high temperature for NO reduction by CO due to the confinement effect of spinel lattice.

scholarly journals The influence of CePO4 nanorods on the CO oxidation activity of Au/GdPO4-rods

RSC Advances ◽  
2018 ◽  
Vol 8 (39) ◽  
pp. 21699-21711
Author(s):  
Yu Huanhuan ◽  
Chen Fayun ◽  
Zhubaolin Zhubaolin ◽  
Huang Weiping ◽  
Zhang Shoumin
Keyword(s):  
Catalytic Activity ◽  
High Temperature ◽  
Co Oxidation ◽  
Oxidation Activity ◽  
Temperature Resistance ◽  
Ultrasound Method ◽  
High Temperature Resistance ◽  
Good Catalytic Activity ◽  
Content Of Gold ◽  
Good Support

A CePO4–GdPO4 composite was prepared by a general ultrasound method and could be a good support for gold nanocatalysts. Au/CePO4–GdPO4 catalysts with a low content of gold showed good catalytic activity, high temperature resistance and stability for CO oxidation.

The Catalytic Effect of Fe on Char-NO Reactions at High-Temperatures

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Bei-Jing Zhong ◽  
Hao Tang
Keyword(s):  
Catalytic Activity ◽  
High Temperature ◽  
Catalytic Effect ◽  
No Reduction ◽  
Specific Activity ◽  
Surface Adsorption ◽  
Stoichiometric Ratio ◽  
Drop Tube ◽  
Drop Tube Furnace ◽  
Loading Amount

The reduction of NO over coal-derived chars and the catalytic effect of Fe on NO-char reaction during char combustion were investigated in a drop-tube furnace in a temperature range of 1323-1523K. The catalytic characteristics of Fe in the NO–char reaction were studied in detail. The results show that iron (Fe) is an effective catalyst for the NO reduction by char derived from de-ashed coal at a high temperature, i.e., the chars with catalysts have high activity in the NO-char reaction. Furthermore, the stoichiometric ratio (SR) in the reaction zone has a significant influence on the catalytic activity of Fe-catalysts, which will be more effective in SR=0.7-0.9. The catalytic activity of Fe depends slightly on its loading amount, while the specific activity of the catalyst obviously decreased with the increasing of the Fe-loading amount. The effect of the temperatures used in the experiments on the NO reduction is small, which suggests the NO-char reaction mainly depends on the diffusion of reactants to char, the reactants' surface adsorption, and the desorption of products under high temperature. However, the effect of the temperature on NO reduction by metal-free char is much more important than that of NO reduction by Fe-loaded char.

Effects of Ni loading on the physicochemical properties of NiOx/CeO2 catalysts and catalytic activity for NO reduction by CO

2020 ◽  
Vol 10 (8) ◽  
pp. 2359-2368 ◽  
Author(s):  
Shuhao Zhang ◽  
Jaeha Lee ◽  
Do Heui Kim ◽  
Taejin Kim
Keyword(s):  
Molecular Structure ◽  
Catalytic Activity ◽  
Physicochemical Properties ◽  
No Reduction ◽  
No Reduction By Co

The NO reduction by CO reaction was investigated using NiOx/CeO2 catalysts with different Ni loadings. Surface NiOx controls the catalytic activity which was related to the molecular structure and reducibility of the catalysts.

scholarly journals Dramatic improvement of NO reduction activity via reversible re-dispersion of CeO2 nanoparticles into Ce+3 atoms on alumina under high temperature reactive treatment

2021 ◽  
Author(s):  
Konstantin Khivantsev ◽  
Hien Pham ◽  
Mark Engelhard ◽  
Xiaohong Li ◽  
Jinshu Tian ◽  
...  
Keyword(s):  
High Temperature ◽  
No Reduction ◽  
Ceo2 Nanoparticles ◽  
Dramatic Improvement ◽  
Ceria Nanoparticles ◽  
No Reduction By Co ◽  
Reduction Activity ◽  
High Temperature Reaction ◽  
Excellent Activity ◽  
Reversible Loss

Ceria nanoparticles supported on gamma-alumina prepared via wet impregnation and sourced commercially have low activity for industrially relevant NO reduction by CO in the presence of steam. These supports contain ceria nanoparticles as well as small (~1%) amount of Ce atomically dispersed and anchored by penta-Al sites. We discovered that treatment of these catalysts at temperatures ~750-950 ºC under the flow of CO and NO in the presence of steam, which typically leads to catalyst deterioration and sintering, in fact, leads to dispersion of ceria nanoparticles into isolated Ce+3 atoms. We extensively characterize them with XPS, FTIR and HAADF-STEM imaging. Their presence changes the alumina surface, as evidenced by XPS and FTIR with probe molecules. Ce+3 ions show dramatically enhanced NO reduction ability in the presence of CO and steam. Infra-red studies reveal close interaction of NO molecules on Ce+3/Alumina surfaces with the formation of N2O species. Heating these samples in oxygen (in wet or dry streams) at 800 ºC and above leads to coalescence of Ce+3 into CeO2 nanoparticles, resulting in reversible loss of activity. Further, reactive treatment of CeO2/Al2O3 under high temperature reaction conditions restores Ce+3 cations as well as catalytic activity. Our study shows reversible redispersion of ceria into isolated Ce+3 cations under conditions where typical catalyst sintering is generally assumed to occur and suggests a pathway to utilize these materials as supports for more effective catalysis. Indeed, supporting only 0.1-0.5 wt% Rh on these CeAl supports, shows synergies between Rh and atomically dispersed Ce ions with excellent activity and stability for NO reduction with CO.

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