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Luo J, Xu S, Xu H, Zhang Z, Chen X, Li M, Tie Y, Zhang H, Chen G, Jiang C. Overview of mechanisms of Fe-based catalysts for the selective catalytic reduction of NO x with NH 3 at low temperature. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:14424-14465. [PMID: 38291211 DOI: 10.1007/s11356-024-32113-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 01/17/2024] [Indexed: 02/01/2024]
Abstract
With the increasingly stringent control of NOx emissions, NH3-SCR, one of the most effective de-NOx technologies for removing NOx, has been widely employed to eliminate NOx from automobile exhaust and industrial production. Researchers have favored iron-based catalysts for their low cost, high activity, and excellent de-NOx performance. This paper takes a new perspective to review the research progress of iron-based catalysts. The influence of the chemical form of single iron-based catalysts on their performance was investigated. In the section on composite iron-based catalysts, detailed reviews were conducted on the effects of synergistic interactions between iron and other elements on catalytic performance. Regarding loaded iron-based catalysts, the catalytic performance of iron-based catalysts on different carriers was systematically examined. In the section on iron-based catalysts with novel structures, the effects of the morphology and crystallinity of nanomaterials on catalytic performance were analyzed. Additionally, the reaction mechanism and poisoning mechanism of iron-based catalysts were elucidated. In conclusion, the paper delved into the prospects and future directions of iron-based catalysts, aiming to provide ideas for the development of iron-based catalysts with better application prospects. The comprehensive review underscores the significance of iron-based catalysts in the realm of de-NOx technologies, shedding light on their diverse forms and applications. The hope is that this paper will serve as a valuable resource, guiding future endeavors in the development of advanced iron-based catalysts.
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Affiliation(s)
- Jianbin Luo
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Song Xu
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Hongxiang Xu
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Zhiqing Zhang
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China.
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China.
| | - Xiaofeng Chen
- Guangxi Automobile Group Co., Ltd, Liuzhou, 545007, China
| | - Mingsen Li
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Yuanhao Tie
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Haiguo Zhang
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Guiguang Chen
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Chunmei Jiang
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
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Ma Y, Liu W, Li Z, Sun Y, Shi M, Nan Z, Song R, Wang L, Guan J. Effect of Metal Complexing on Mn–Fe/TS-1 Catalysts for Selective Catalytic Reduction of NO with NH3. Molecules 2023; 28:molecules28073068. [PMID: 37049831 PMCID: PMC10095777 DOI: 10.3390/molecules28073068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
TS-1 zeolite with desirable pore structure, an abundance of acidic sites, and good thermal stability promising as a support for the selective catalytic reduction of NO with NH3 (NH3-SCR). Herein, a series of Mn–Fe/TS-1 catalysts have been synthesized, adopting tetraethylenepentamine (TEPA) as a metal complexing agent using the one-pot hydrothermal method. The introduced TEPA can not only increase the loading of active components but also prompts the formation of a hierarchical structure through decreasing the size of TS-1 nanocrystals to produce intercrystalline mesopores during the hydrothermal crystallization process. The optimized Mn–Fe/TS-1(R-2) catalyst shows remarkable NH3-SCR performance. Moreover, it exhibits excellent resistance to H2O and SO2 at low temperatures. The characterization results indicate that Mn–Fe/TS-1(R-2) possesses abundant surface Mn4+ and Fe2+ and chemisorbed oxygen, strong reducibility, and a high Brønsted acid amount. For comparison, Mn–Fe/TiO2 displays a narrower active temperature window due to its poor thermostability.
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Affiliation(s)
- Yuanyuan Ma
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
- Correspondence: (Y.M.); (J.G.)
| | - Wanting Liu
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Zhifang Li
- College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006, China
| | - Yuhang Sun
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Mingyuan Shi
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Zheng Nan
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Ruotong Song
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Liying Wang
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China
| | - Jingqi Guan
- Institute of Physical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130021, China
- Correspondence: (Y.M.); (J.G.)
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Mu G, Liu S, Liu Q, Liu S, Zhang X. Low-Dose Element-Doped CeCrM/TiO 2 (M = La, Cu, Fe, LaCu, LaFe) Catalyst for Low-Temperature NH 3-SCR Process: Synergistic Effect of LaCu/LaFe. ACS OMEGA 2022; 7:37694-37704. [PMID: 36312429 PMCID: PMC9608399 DOI: 10.1021/acsomega.2c04603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
A series of CeCrM/TiO2 (M = La, Cu, Fe, LaCu, LaFe) catalysts were prepared via impregnation method and are employed as low-temperature NH3-SCR catalysts. The present study investigates the low-dose element doping on the TiO2-supported catalyst to improve the NH3-SCR performance. And CeCrLaCu/TiO2 exhibited the best catalytic performance (NO conversion approaching 100% at 260-420 °C). The characterization results show that the synergistic effect of LaCu and LaFe on the catalytic performance was more obvious than that of Cu, Fe, and La alone. The doping of LaCu/LaFe decreased the specific surface area of the catalyst but increased the dispersion, surface acidity, and reducibility of the catalyst. Moreover, LaCu/LaFe promoted the formation of valence state distribution and oxygen vacancy content on the surface of the catalyst. There were more Ce3+, Cr6+, Cu+, and oxygen adsorbed on the surface of the CeCrLaCu/TiO2 catalyst. H2-TPR analysis showed that the synergistic effect of LaCu was more likely to promote the reduction of Cr and Cu and increase the reduction degree of metal oxides. However, Fe is easier to coordinate with La, thus improving the redox performance of the catalyst. Compared with CeCrLaFe/TiO2, the ammonia adsorption capacity of CeCrLaCu/TiO2 is better. Therefore, the synergistic effect of LaCu can promote the reaction performance of NH3-SCR better.
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Abstract
In recent years, low-temperature SCR (Selective Catalytic Reduction) denitrification technology has been popularized in non-power industries and has played an important role in the control of industrial flue gas NOx emissions in China. Currently, the most commonly used catalysts in industry are V2O5-WO3(MoO3)/TiO2, MnO2-based catalysts, CeO2-based catalysts, MnO2-CeO2 catalysts and zeolite SCR catalysts. The flue gas emitted during industrial combustion usually contains SO2, moisture and alkali metals, which can affect the service life of SCR catalysts. This paper summarizes the mechanism of catalyst poisoning and aims to reduce the negative effect of NH4HSO4 on the activity of the SCR catalyst at low temperatures in industrial applications. It also presents the outstanding achievements of domestic companies in denitrification in the non-power industry in recent years. Much progress has been made in the research and application of low-temperature NH3-SCR, and with the renewed demand for deeper NOx treatments, new technologies with lower energy consumption and more functions need to be developed.
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Yi L, Xie J, Li C, Shan J, Liu Y, Lv J, Li M, Gao L. LaO x modified MnO x loaded biomass activated carbon and its enhanced performance for simultaneous abatement of NO and Hg 0. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:2258-2275. [PMID: 34365596 DOI: 10.1007/s11356-021-15752-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
A battery of agricultural straw derived biomass activated carbons supported LaOx modified MnOx (LaMn/BACs) was prepared by a facile impregnation method and then tested for simultaneous abatement of NO and Hg0. 15%LaMn/BAC manifested excellent removal efficiency of Hg0 (100%) and NO (86.7%) at 180 °C, which also exhibited splendid resistance to SO2 and H2O. The interaction between Hg0 removal and NO removal was explored; thereinto, Hg0 removal had no influence on NO removal, while NO removal preponderated over Hg0 removal. The inhibitory effect of NH3 was greater than the accelerative effect of NO and O2 on Hg0 removal. The physicochemical characterization of related samples was characterized by SEM, XRD, BET, H2-TPR, NH3-TPD, and XPS. After incorporating suitable LaOx into 15%Mn/BAC, the synergistic effect between LaOx and MnOx contributed to the improvement of BET surface area and total pore volume, the promotion of redox ability, surface active oxygen species, and acid sites, inhibiting the crystallization of MnOx. 15%LaMn/BAC has the best catalytic oxidation activity at low temperature. That might be answerable for superior performance and preferable tolerance to SO2 and H2O. The results indicated that 15%LaMn/BAC was a promising catalyst for simultaneous abatement of Hg0 and NO at low temperature.
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Affiliation(s)
- Lei Yi
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Jinke Xie
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Caiting Li
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China
| | - Jian Shan
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Yingyun Liu
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Junwen Lv
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Mi Li
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China
| | - Lei Gao
- School of Resources Environment and Safety Engineering, University of South China, Hengyang, 421001, People's Republic of China.
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.
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Significant promoting effect of La doping on the wide temperature NH3-SCR performance of Ce and Cu modified ZSM-5 catalysts. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2021.122700] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sun X, Liu Q, Liu S, Zhang X, Liu S. Improvement of low-temperature NH 3-SCR catalytic performance over nitrogen-doped MO x -Cr 2O 3-La 2O 3/TiO 2-N (M = Cu, Fe, Ce) catalysts. RSC Adv 2021; 11:22780-22788. [PMID: 35480444 PMCID: PMC9034305 DOI: 10.1039/d1ra03845a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/21/2021] [Indexed: 11/21/2022] Open
Abstract
A series of MO x -Cr2O3-La2O3/TiO2-N (M = Cu, Fe, Ce) catalysts with nitrogen doping were prepared via the impregnation method. Comparing the low-temperature NH3-SCR activity of the catalysts, CeCrLa/Ti-N (xCeO2-yCr2O3-zLa2O3/TiO2-N) exhibited the best catalytic performance (NO conversion approaching 100% at 220-460 °C). The physico-chemical properties of the catalysts were characterized by XRD, BET, SEM, XPS, H2-TPR, NH3-TPD and in situ DRIFTS. From the XRD and SEM results, N doping affects the crystalline growth of anatase TiO2 and MO x (M = Cu, Fe, Ce, Cr, La) which were well dispersed over the support. Moreover, the doping of N promotes the increase of the Cr6+/Cr ratio and Ce3+/Ce ratio, and the surface chemical adsorption oxygen content, which suggested the improvement of the redox properties of the catalyst. And the surface acid content of the catalyst increased with the doping of N, which is related to CeCrLa/TiO2-N having the best catalytic activity at high temperature. Therefore, the CeCrLa/TiO2-N catalyst exhibited the best NH3-SCR performance and the redox performance of the catalysts is the main factor affecting their activity. Furthermore, in situ DRIFTS analysis indicates that Lewis-acid sites are the main adsorption sites for ammonia onto CeCrLa/TiO2-N and the catalyst mainly follows the L-H mechanism.
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Affiliation(s)
- Xiaoyi Sun
- College of Chemical and Biological Engineering, Shandong University of Science and Technology Qingdao 266590 PR China
| | - Qingjie Liu
- College of Chemical and Biological Engineering, Shandong University of Science and Technology Qingdao 266590 PR China
| | - Shuai Liu
- College of Chemical and Biological Engineering, Shandong University of Science and Technology Qingdao 266590 PR China
| | - Xintang Zhang
- College of Chemical and Biological Engineering, Shandong University of Science and Technology Qingdao 266590 PR China
| | - Shanshan Liu
- College of Chemical and Biological Engineering, Shandong University of Science and Technology Qingdao 266590 PR China
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Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts. Catalysts 2021. [DOI: 10.3390/catal11050618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism.
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