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Effect of MnOx/α-Fe2O3 Prepared from Goethite on Selective Catalytic Reduction of NO with NH3. J CHEM-NY 2022. [DOI: 10.1155/2022/5049161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A low-cost goethite and manganese acetate were used to prepare a MnOx/α-Fe2O3 composite catalyst by simple impregnation method for novel high-efficiency selective catalytic reduction (SCR) of NO with NH3, and its denitration performance of composite catalyst under different conditions was investigated in a thermal fixed-bed catalytic reaction system. The results showed that MnOx/α-Fe2O3 with Mn/Fe molar ratio of 0.1 and calcination temperature of 400 °C had the best low-temperature catalytic activity and wider reaction temperature window compared with α-Fe2O3. It achieved over 90% NO conversion efficiency with a space velocity of 72,000 h−1 at 200~350 °C and possessed a good resistance of H2O and SO2. Characterization by XRD, BET, H2-TPR, and NH3-TPD revealed that the main reason for the high catalytic activity of MnOx(0.1)/α-Fe2O3(400) was that the addition of Mn changed phase types of catalyst and valence composition of Fe, resulting in a larger specific surface area, more acidic sites, and higher redox performance.
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Zhang J, Guo Q, Wu W, Shao S, Li Z, Liu Y, Jiao W. Preparation of Fe-MnOX/AC by high gravity method for heterogeneous catalytic ozonation of phenolic wastewater. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117667] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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3
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Mechanistic insight into the promoting effect of partial substitution of Mn by Ce on N2 selectivity of MnTiO catalyst for NH3-SCR of NO. J Taiwan Inst Chem Eng 2022. [DOI: 10.1016/j.jtice.2022.104269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Zhai G, Han Z, Du H, Gao Y, Pan X. An investigation on the promoting effect of Pr modification on SO 2 resistance over MnO x catalysts for selective reduction of NO with NH 3. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:17295-17308. [PMID: 34661840 DOI: 10.1007/s11356-021-17006-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Pr-modified MnOx catalyst was synthesized through a facile co-precipitation process, and the results showed that MnPrOx catalyst exhibited much better selective catalytic reduction (SCR) activity and SO2 resistance performance than pristine MnOx catalyst. The addition of Pr in MnOx catalyst led to a complete NO conversion efficiency in 120-220 °C. Moreover, Pr-modified MnOx catalyst exhibited a superior resistance to H2O and SO2 compared with MnOx catalyst. After exposing to SO2 and H2O for 4 h, the NO conversion efficiency of MnPrOx catalyst could remain to 87.6%. The characterization techniques of XRD, BET, hydrogen-temperature programmed reduction (H2-TPR), ammonia-temperature programmed desorption (NH3-TPD), XPS, TG and in situ diffuse reflectance infrared spectroscopy (DRIFTS) were adopted to further explore the promoting effect of Pr doping in MnOx catalyst on SO2 resistance performance. The results showed that MnPrOx catalyst had larger specific surface area, stronger reducibility, and more L acid sites compared with MnOx catalyst. The relative percentage of Mn4+/Mnn+ on the MnPrOx-S catalyst surface was also much higher than those of MnOx catalyst. Importantly, when SO2 exists in feed gas, PrOx species in MnPrOx catalyst would preferentially react with SO2, thus protecting the Mn active sites. In addition, the introduction of Pr might promote the reaction between SO2 and NH3 rather than between SO2 and Mn active sites, which was also conductive to protect the Mn active sites to a great extent. Since the presence of SO2 in feed gas had little effect on NH3 adsorption on the MnPrOx catalyst surface, and the inhibiting effect of SO2 on NO adsorption was alleviated, SCR reactions could still proceed in a near-normal way through the Eley-Rideal (E-R) mechanism on Pr-modified MnOx catalyst, while SCR reactions through the Langmuir-Hinshelwood (L-H) mechanism were suppressed slightly.
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Affiliation(s)
- Guangpeng Zhai
- Marine Engineering College, Dalian Maritime University, No.1, Linghai Road, Dalian, 116026, China
| | - Zhitao Han
- Marine Engineering College, Dalian Maritime University, No.1, Linghai Road, Dalian, 116026, China.
- Liaoning Research, Center for Marine Internal Combustion Engine Energy-Saving, Dalian, 116026, China.
| | - Huan Du
- Marine Engineering College, Dalian Maritime University, No.1, Linghai Road, Dalian, 116026, China
| | - Yu Gao
- Marine Engineering College, Dalian Maritime University, No.1, Linghai Road, Dalian, 116026, China
| | - Xinxiang Pan
- Marine Engineering College, Dalian Maritime University, No.1, Linghai Road, Dalian, 116026, China.
- Liaoning Research, Center for Marine Internal Combustion Engine Energy-Saving, Dalian, 116026, China.
- Guangdong Ocean University, Zhanjiang, 524088, Guangdong, China.
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Zang P, Liu J, Liu X, Zhang G, Chen J, Li J, Zhang Y. Remarkable enhancement in the N 2 selectivity of NH 3-SCR over the CeNb 3Fe 0.3/TiO 2 catalyst in the presence of chlorobenzene. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:19309-19323. [PMID: 34713406 DOI: 10.1007/s11356-021-17116-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
The simultaneous removal of NOx and dioxins is the frontier of environmental catalysis, which is still in the initial stage and poses several challenges. In this study, a series of CeNb3Fex/TiO2 (x = 0, 0.3, 0.6, and 1.0) catalysts were prepared by the sol-gel method and examined for the synergistic removal of NOx and CB. The CeNb3Fe0.3/TiO2 catalyst exhibits an optimum catalytic performance, with an NOx conversion greater than 95% at 260-380 °C. It also exhibits an optimal CB oxidation activity, in which CB promoted both the NOx conversion and N2 selectivity below 250 °C. Moreover, the more favorable ratios of Ce4+ to Ce3+ and plentiful surface-adsorbed oxygen species are the reasons why CeNb3Fe0.3/TiO2 catalyst has better catalytic activity than other catalysts at the lower temperature. Simultaneously, owing to the modulation of Fe to the redox properties of Ce and Nb, the large number of oxygen vacancies and acid sites was generated, and the CeNb3Fe0.3/TiO2 catalyst is beneficial to NOx reduction and CB oxidation. Furthermore, the results of in situ DRIFTS study reveal the NH3-SCR reactions over CeNb3Fe0.3/TiO2 catalysts are mainly conformed to by the L-H mechanism (< 350 °C) and E-R mechanism (> 350 °C), respectively, and the multi-pollutant conversion mechanism in the synergistic reaction was systematically studied.
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Affiliation(s)
- Pengchao Zang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, People's Republic of China
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, People's Republic of China
| | - Jun Liu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, People's Republic of China.
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, People's Republic of China.
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, National Engineering, Tsinghua University, Beijing, 100084, People's Republic of China.
| | - Xiaoqing Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, National Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
- School of Environment and Safety Engineering, North University of China, Taiyuan, 030051, Shanxi, People's Republic of China
| | - Guojie Zhang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, People's Republic of China.
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, People's Republic of China.
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, National Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, National Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Yongfa Zhang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, People's Republic of China
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, People's Republic of China
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Han Z, Du H, Xu D, Gao Y, Yang S, Song L, Dong J, Pan X. Fe and Mn mixed oxide catalysts supported on Sn-modified TiO 2 for the selective catalytic reduction of NO with NH 3 at low temperature. NEW J CHEM 2022. [DOI: 10.1039/d1nj05290j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
FeMn/SnxTiO2 catalysts were synthesized by introducing Sn as an additive to modify TiO2 supports, and the Sn doping could improve the SO2 tolerance and low-temperature SCR activity significantly.
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Affiliation(s)
- Zhitao Han
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Huan Du
- China Waterborne Transport Research Institute, Beijing 100088, China
| | - Duo Xu
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Yu Gao
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Shaolong Yang
- School of Naval Architecture and Ocean Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Liguo Song
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jingming Dong
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Xinxiang Pan
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
- School of Electronic and Information Technology, Guangdong Ocean University, Zhanjiang 524088, China
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Li C, Han Z, Wang X, Gao Y, Wang Z, Pan X. The promoting effect of support pretreatment with sulfate acid on the Ca resistance of a CeO 2/ZrO 2 catalyst for NH 3-SCR of NO x with NH 3. NEW J CHEM 2022. [DOI: 10.1039/d2nj02919g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CaSO4 was formed through the reaction between S and Ca to relieve the effect of Ca-poisoning on the catalyst.
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Affiliation(s)
- Chenglong Li
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Zhitao Han
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Xinxin Wang
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Yu Gao
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Zhen Wang
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Xinxiang Pan
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
- School of Electronic and Information Technology, Guangdong Ocean University, Zhanjiang 524088, China
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Zabihi V, Eikani MH, Ardjmand M, Latifi SM, Salehirad A. Selective catalytic reduction of NO by Fe-Mn nanocatalysts: effect of structure type. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:39159-39167. [PMID: 33751352 DOI: 10.1007/s11356-021-13119-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
One of the most prominent features of selective catalytic reduction (SCR) of NOx is using a well-structured catalyst to advance the reaction in a desirable condition. At the present work, various crystal structures of Fe-Mn nanocatalysts, FeMn2O4 spinel, FeMnO3 perovskite and Fe2O3 (hematite)/Mn2O3 (bixbyite) nanocatalysts fabricated by co-precipitation method were evaluated for selective catalytic reduction of NO by NH3 (NH3-SCR). The studies specified that the crystal structure type had a high impact on structural properties and thereby the catalytic performance of the samples. The physicochemical characteristics of the nanocatalysts including molar ratio of metals, phase composition, crystallite size, particle size distribution, specific surface area, average pore diameter, pore volume, agglomeration degree, and amount and strength of the acidic site on the catalysts surfaces have been distinguished. From the catalytic activity evaluation, it was identified that the perovskite nanocatalyst had the best performance in NH3-SCR reaction.
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Affiliation(s)
- Vahid Zabihi
- Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad Hasan Eikani
- Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran.
| | - Mehdi Ardjmand
- Department of Chemical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Seyed Mahdi Latifi
- Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
| | - Alireza Salehirad
- Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
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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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10
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Selective catalytic reduction of NO by Co-Mn based nanocatalysts. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2021. [DOI: 10.1515/ijcre-2020-0240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.
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11
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Li X, Han Z, Shi Q, Wang X, Wu X, Gao Y, Li C, Liu G. Characterization of WMnCeTiO x catalysts prepared by different methods for the selective reduction of NO with NH 3. NEW J CHEM 2021. [DOI: 10.1039/d1nj03891e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
WMnCeTiOx(CP) catalysts showed excellent NH3-SCR activity and better SO2 tolerance.
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Affiliation(s)
- Xiaodi Li
- School of Resources and Environmental Sciences, XinJiang University, Wulumuqi, 830000, China
| | - Zhitao Han
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
- Liaoning Research Center for Marine Internal Combustion Engine Energy-Saving, Dalian 116026, China
| | - Qingdong Shi
- School of Resources and Environmental Sciences, XinJiang University, Wulumuqi, 830000, China
| | - Xinxin Wang
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Xitian Wu
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Yu Gao
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Chenglong Li
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
| | - Gang Liu
- Marine Engineering College, Dalian Maritime University, No. 1, Linghai Road, Dalian 116026, China
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