scholarly journals Influence of Copper on the Catalytic Activity of Supported Rhodium Catalysts in the Reactions of CO Oxidation and NO Reduction

2017 ◽  
Vol 4 (4) ◽  
pp. 265
Author(s):  
L.A. Petrov ◽  
J. Soria ◽  
R. Cataluna
Keyword(s):  
Catalytic Activity ◽  
Thermal Treatment ◽  
Low Temperature ◽  
Co Oxidation ◽  
No Reduction ◽  
Promoting Effect ◽  
Catalytic Activities ◽  
Cu Catalysts ◽  
Temperature Programmed ◽  
Positive Effect

<p>The catalytic activity of Cu, Rh, and Rh/Cu, catalysts supported on Al<sub>2</sub>O<sub>3</sub>, CeO<sub>2</sub> and CeO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> in reactions of CO oxidation and NO reduction has been studied in temperature-programmed regime. Addition of Cu to Rh catalysts decreases temperature at which 5 and 50% degree of conversion, while end of reaction temperature is not influenced by presence of Cu. The presence of Cu has positive effect on the activity of Rh containing catalysts in the low temperature region. Cu has noticeable promoting effect mainly for the catalytic activity in the reaction of CO oxidation and in smaller extent for the reaction of NO reduction. Preliminary redox treatment of the catalysts decreases the light off temperature in the reactions of CO oxidation and in NO reduction. Thermal treatment at temperatures up to 973 K does not have sensible effect on the catalytic activities of all studied catalysts. Calcination at 1073 K, however, strongly decreases the catalytic activity of Rh/Cu/CeO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> catalysts.</p>

Thermal Treatment Effect on Catalytic Activity of Au/TiO2 for CO Oxidation

2014 ◽  
Vol 548-549 ◽  
pp. 254-258
Author(s):  
Asif Mahmood ◽  
Shahid M. Ramay ◽  
Yousef Al-Zeghayer ◽  
Sajjad Haider ◽  
Muhammad Ali Shar ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Treatment ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Preferential Oxidation ◽  
Reaction Heat ◽  
Oxidation Performance ◽  
Positive Effect

A novel and well-organized study for the synthesis and enhanced catalytic activity of Au/TiO2catalysts has been developed. A momentous improvement in the catalytic activity of Au/TiO2in CO oxidation and preferential oxidation reaction by thermal treatment has been studied. Au/TiO2catalyst (Au (1 wt.%) supported on TiO2) was prepared by conventional deposition-precipitation method with NaOH followed by washing, drying and calcination in air at 400 °C for 4 h. Thermal treatment of Au/TiO2was performed at 450 °C under 0.05 mTorr. The activity of the catalysts has been examined in the reaction of CO oxidation and preferential oxidation (PROX) at 25-250 °C. The catalytic performance was found to be strongly affected by thermal treatment of the prepared catalyst prior to the reaction. Heat treatment after Au deposition has a positive effect on the CO oxidation performance. This is attributed to the introduction of a stronger interaction between the oxide and Au which improves the catalytic activity.

scholarly journals Electrical Promotion-Assisted Automotive Exhaust Catalyst: Highly Active and Selective NO Reduction to N2 at Low-Temperatures

2021 ◽  
Author(s):  
Yuki Omori ◽  
Ayaka Shigemoto ◽  
Kohei Sugihara ◽  
Takuma Higo ◽  
Toru Uenishi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Electric Field ◽  
Low Temperatures ◽  
No Reduction ◽  
Lattice Oxygen ◽  
Pd Catalyst ◽  
Highly Active ◽  
Automotive Exhaust Catalyst ◽  
Activated Surface

Pd catalyst (Pd/Ce<sub>0.7</sub>Zr<sub>0.3</sub>O<sub>2</sub>) in an electric field exhibits extremely high three-way catalytic activity (TWC: NO-C<sub>3</sub>H<sub>6</sub>-CO-O<sub>2</sub>-H<sub>2</sub>O). By applying an electric field to the semiconductor catalyst, low-temperature operation of TWC can be achieved even at 473 K by virtue of the activated surface-lattice oxygen.

scholarly journals CO Oxidation over Metal Oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2) Doped CuO-Based Catalysts Supported on Mesoporous Ce0.8Zr0.2O2 with Intensified Low-Temperature Activity

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 724 ◽  
Author(s):  
Yan Cui ◽  
Leilei Xu ◽  
Mindong Chen ◽  
Chufei Lv ◽  
Xinbo Lian ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Co Oxidation ◽  
Active Sites ◽  
Earth Metal ◽  
High Dispersion ◽  
Impregnation Method ◽  
X Ray

CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2 support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2 temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3 showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2 solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.

Enhanced catalytic activity of Au-CeO2/Al2O3 monolith for low-temperature CO oxidation

2019 ◽  
Vol 129 ◽  
pp. 105729 ◽  
Author(s):  
Zhiwen Li ◽  
Huan Wang ◽  
Weiwei Zhao ◽  
Xin Xu ◽  
Quan Jin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Low Temperature Co Oxidation

Low-temperature CO oxidation over CeO2 and CeO2@Co3O4 core–shell microspheres

2017 ◽  
Vol 41 (22) ◽  
pp. 13418-13424 ◽  
Author(s):  
Lu Zhang ◽  
Li Zhang ◽  
Guancheng Xu ◽  
Chi Zhang ◽  
Xin Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Core Shell ◽  
Synergistic Interactions ◽  
Low Temperature Co Oxidation

The excellent CO catalytic activity and stability of CeO2@Co3O4 composite were ascribed to the synergistic interactions between Co3O4 and CeO2.

scholarly journals Tailoring the reducibility and catalytic activity of CuO nanoparticles for low temperature CO oxidation

RSC Advances ◽  
2018 ◽  
Vol 8 (35) ◽  
pp. 19499-19511 ◽  
Author(s):  
Abdallah F. Zedan ◽  
Assem T. Mohamed ◽  
M. Samy El-Shall ◽  
Siham Y. AlQaradawi ◽  
Amina S. AlJaber
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Copper Oxide ◽  
Co Oxidation ◽  
Cuo Nanoparticles ◽  
Low Temperature Co Oxidation

Copper oxide (CuO) nanoparticles of tailored reducibility could be used as inexpensive, efficient and durable catalysts for CO oxidation at low temperature.

Pt NPs immobilized on a N-doped graphene@Al2O3 hybrid support as robust catalysts for low temperature CO oxidation

2018 ◽  
Vol 54 (79) ◽  
pp. 11168-11171 ◽  
Author(s):  
Zhimin Jia ◽  
Fei Huang ◽  
Jiangyong Diao ◽  
Jiayun Zhang ◽  
Jia Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Platinum Nanoparticles ◽  
Support Interaction ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Low Temperature Co Oxidation ◽  
Doped Graphene ◽  
Strong Metal Support Interaction

Platinum nanoparticles (Pt NPs) immobilized on a N-doped graphene@Al2O3 hybrid support (Al2O3@CNx) were synthesized and exhibit superior catalytic activity for low temperature CO oxidation, due to a strong metal–support interaction between Pt NPs and the N-doped.

scholarly journals Insights into the promotion role of phosphorus doping on carbon as a metal-free catalyst for low-temperature selective catalytic reduction of NO with NH3

RSC Advances ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 12908-12919
Author(s):  
Weifeng Li ◽  
Shuangling Jin ◽  
Rui Zhang ◽  
Yabin Wei ◽  
Jiangcan Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
No Reduction ◽  
Catalytic Reduction ◽  
Carbon Aerogels ◽  
Phosphorus Doping ◽  
Reduction Of No ◽  
Metal Free

P species can effectively enhance the catalytic activity of carbon aerogels for NO reduction at low temperature.

scholarly journals Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

2013 ◽  
Vol 4 ◽  
pp. 111-128 ◽  
Author(s):  
Lu-Cun Wang ◽  
Yi Zhong ◽  
Haijun Jin ◽  
Daniel Widmann ◽  
Jörg Weissmüller ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Scale Effects ◽  
Structural Parameters ◽  
Kinetic Measurements ◽  
X Ray ◽  
Low Temperature Co Oxidation

The catalytic properties of nanostructured Au and their physical origin were investigated by using the low-temperature CO oxidation as a test reaction. In order to distinguish between structural effects (structure–activity correlations) and bimetallic/bifunctional effects, unsupported nanoporous gold (NPG) samples prepared from different Au alloys (AuAg, AuCu) by selective leaching of a less noble metal (Ag, Cu) were employed, whose structure (surface area, ligament size) as well as their residual amount of the second metal were systematically varied by applying different potentials for dealloying. The structural and chemical properties before and after 1000 min reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The catalytic behavior was evaluated by kinetic measurements in a conventional microreactor and by dynamic measurements in a temporal analysis of products (TAP) reactor. The data reveal a clear influence of the surface contents of residual Ag and Cu species on both O2 activation and catalytic activity, while correlations between activity and structural parameters such as surface area or ligament/crystallite size are less evident. Consequences for the mechanistic understanding and the role of the nanostructure in these NPG catalysts are discussed.

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