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La Greca E, Kharlamova TS, Grabchenko MV, Consentino L, Savenko DY, Pantaleo G, Kibis LS, Stonkus OA, Vodyankina OV, Liotta LF. Ag Catalysts Supported on CeO 2, MnO 2 and CeMnO x Mixed Oxides for Selective Catalytic Reduction of NO by C 3H 6. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:873. [PMID: 36903752 PMCID: PMC10005331 DOI: 10.3390/nano13050873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/23/2023] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
In the present study CeO2, MnO2 and CeMnOx mixed oxide (with molar ratio Ce/Mn = 1) were prepared by sol-gel method using citric acid as a chelating agent and calcined at 500 °C. The silver catalysts (1 wt.% Ag) over the obtained supports were synthesized by the incipient wetness impregnation method with [Ag(NH3)2]NO3 aqueous solution. The selective catalytic reduction of NO by C3H6 was investigated in a fixed-bed quartz reactor using a reaction mixture composed of 1000 ppm NO, 3600 ppm C3H6, 10 vol.% O2, 2.9 vol.% H2 and He as a balance gas, at WHSV of 25,000 mL g-1 h-1.The physical-chemical properties of the as-prepared catalysts were studied by several characterization techniques, such as X-ray fluorescence analysis, nitrogen adsorption/desorption, X-ray analysis, Raman spectroscopy, transmission electron microscopy with analysis of the surface composition by X-ray energy dispersive spectroscopy and X-ray photo-electron spectroscopy. Silver oxidation state and its distribution on the catalysts surface as well as the support microstructure are the main factors determining the low temperature activity in NO selective catalytic reduction. The most active Ag/CeMnOx catalyst (NO conversion at 300 °C is 44% and N2 selectivity is ~90%) is characterized by the presence of the fluorite-type phase with high dispersion and distortion. The characteristic "patchwork" domain microstructure of the mixed oxide along with the presence of dispersed Ag+/Agnδ+ species improve the low-temperature catalyst of NO reduction by C3H6 performance compared to Ag/CeO2 and Ag/MnOx systems.
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Affiliation(s)
- Eleonora La Greca
- Institute for the Study of Nanostructured Materials (ISMN), (Italian) National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy
| | - Tamara S. Kharlamova
- Laboratory of Catalytic Research, Tomsk State University, Lenin Ave. 36, 634050 Tomsk, Russia
| | - Maria V. Grabchenko
- Laboratory of Catalytic Research, Tomsk State University, Lenin Ave. 36, 634050 Tomsk, Russia
| | - Luca Consentino
- Institute for the Study of Nanostructured Materials (ISMN), (Italian) National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy
| | - Daria Yu Savenko
- Laboratory of Catalytic Research, Tomsk State University, Lenin Ave. 36, 634050 Tomsk, Russia
| | - Giuseppe Pantaleo
- Institute for the Study of Nanostructured Materials (ISMN), (Italian) National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy
| | - Lidiya S. Kibis
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Ave. 5, 630090 Novosibirsk, Russia
| | - Olga A. Stonkus
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Ave. 5, 630090 Novosibirsk, Russia
| | - Olga V. Vodyankina
- Laboratory of Catalytic Research, Tomsk State University, Lenin Ave. 36, 634050 Tomsk, Russia
| | - Leonarda Francesca Liotta
- Institute for the Study of Nanostructured Materials (ISMN), (Italian) National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy
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Chen J, Huang W, Bao S, Zhang W, Liang T, Zheng S, Yi L, Guo L, Wu X. A review on the characterization of metal active sites over Cu-based and Fe-based zeolites for NH 3-SCR. RSC Adv 2022; 12:27746-27765. [PMID: 36320283 PMCID: PMC9517171 DOI: 10.1039/d2ra05107a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/20/2022] [Indexed: 06/07/2024] Open
Abstract
Cu-based and Fe-based zeolites are promising catalysts for NH3-SCR due to their high catalytic activity, wide temperature window and good hydrothermal stability, while the detailed investigation of NH3-SCR mechanism should be based on the accurate determination of active metal sites. This review systematically summarizes the qualitative and quantitative determination of metal active sites in Cu-based or Fe-based zeolites for NH3-SCR reactions based on advanced characterization methods such as UV-vis absorption (UV-vis), temperature-programmed reduction with H2 (H2-TPR), X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure spectroscopy (XAFS), Infrared spectroscopy (IR), Electron paramagnetic resonance (EPR), Mössbauer spectroscopy and DFT calculations. The application and limitations of different characterization methods are also discussed to provide insights for further study of the NH3-SCR reaction mechanism over metal-based zeolites.
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Affiliation(s)
- Jialing Chen
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Wei Huang
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Sizhuo Bao
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Wenbo Zhang
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Tingyu Liang
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology Wuhan 430205 China
| | - Shenke Zheng
- Hubei Key Laboratory for Processing and Application of Catalytic Materials, School of Chemistry and Chemical Engineering, Huanggang Normal University Huanggang 438000 China
| | - Lan Yi
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Li Guo
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
| | - Xiaoqin Wu
- Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology Wuhan 430081 China +86 027 68862335
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The Emergence of the Ubiquity of Cerium in Heterogeneous Oxidation Catalysis Science and Technology. Catalysts 2022. [DOI: 10.3390/catal12090959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Research into the incorporation of cerium into a diverse range of catalyst systems for a wide spectrum of process chemistries has expanded rapidly. This has been evidenced since about 1980 in the increasing number of both scientific research journals and patent publications that address the application of cerium as a component of a multi-metal oxide system and as a support material for metal catalysts. This review chronicles both the applied and fundamental research into cerium-containing oxide catalysts where cerium’s redox activity confers enhanced and new catalytic functionality. Application areas of cerium-containing catalysts include selective oxidation, combustion, NOx remediation, and the production of sustainable chemicals and materials via bio-based feedstocks, among others. The newfound interest in cerium-containing catalysts stems from the benefits achieved by cerium’s inclusion, which include selectivity, activity, and stability. These benefits arise because of cerium’s unique combination of chemical and thermal stability, its redox active properties, its ability to stabilize defect structures in multicomponent oxides, and its propensity to stabilize catalytically optimal oxidation states of other multivalent elements. This review surveys the origins and some of the current directions in the research and application of cerium oxide-based catalysts.
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Li S, Zheng Z, Zhao Z, Wang Y, Yao Y, Liu Y, Zhang J, Zhang Z. CeO 2 Nanoparticle-Loaded MnO 2 Nanoflowers for Selective Catalytic Reduction of NO x with NH 3 at Low Temperatures. Molecules 2022; 27:molecules27154863. [PMID: 35956809 PMCID: PMC9369832 DOI: 10.3390/molecules27154863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
CeO2 nanoparticle-loaded MnO2 nanoflowers, prepared by a hydrothermal method followed by an adsorption-calcination technique, were utilized for selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. The effects of Ce/Mn ratio and thermal calcination temperature on the NH3-SCR activity of the CeO2-MnO2 nanocomposites were studied comprehensively. The as-prepared CeO2-MnO2 catalysts show high NOx reduction efficiency in the temperature range of 150-300 °C, with a complete NOx conversion at 200 °C for the optimal sample. The excellent NH3-SCR performance could be ascribed to high surface area, intimate contact, and strong synergistic interaction between CeO2 nanoparticles and MnO2 nanoflowers of the well-designed composite catalyst. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) characterizations evidence that the SCR reaction on the surface of the CeO2-MnO2 nanocomposites mainly follows the Langmuir-Hinshelwood (L-H) mechanism. Our work provides useful guidance for the development of composite oxide-based low temperature NH3-SCR catalysts.
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Affiliation(s)
- Shun Li
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Zuquan Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Zhicheng Zhao
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
| | - Youling Wang
- Shunde Graduate School, University of Science and Technology Beijing, Foshan 528399, China;
| | - Yao Yao
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
| | - Yong Liu
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
| | - Jianming Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China;
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
| | - Zuotai Zhang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
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Advances in Designing Efficient La-Based Perovskites for the NOx Storage and Reduction Process. Catalysts 2022. [DOI: 10.3390/catal12060593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To overcome the inherent challenge of NOx reduction in the net oxidizing environment of diesel engine exhaust, the NOx storage and reduction (NSR) concept was proposed in 1995, soon developed and commercialized as a promising DeNOx technique over the past two decades. Years of practice suggest that it is a tailor-made technique for light-duty diesel vehicles, with the advantage of being space saving, cost effective, and efficient in NOx abatement; however, the over-reliance of NSR catalysts on high loadings of Pt has always been the bottleneck for its wide application. There remains fervent interest in searching for efficient, economical, and durable alternatives. To date, La-based perovskites are the most explored promising candidate, showing prominent structural and thermal stability and redox property. The perovskite-type oxide structure enables the coupling of redox and storage centers with homogeneous distribution, which maximizes the contact area for NOx spillover and contributes to efficient NOx storage and reduction. Moreover, the wide range of possible cationic substitutions in perovskite generates great flexibility, yielding various formulations with interesting features desirable for the NSR process. Herein, this review provides an overview of the features and performances of La-based perovskite in NO oxidation, NOx storage, and NOx reduction, and in this way comprehensively evaluates its potential to substitute Pt and further improve the DeNOx efficiency of the current NSR catalyst. The fundamental structure–property relationships are summarized and highlighted to instruct rational catalyst design. The critical research needs and essential aspects in catalyst design, including poisoner resistance and catalyst sustainability, are finally addressed to inspire the future development of perovskite material for practical application.
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