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Li G, Zhang Y, Wu P, Shen K, Zhang S, Ding S. Improved activity and significant SO 2 tolerance of Sb-Pd-V oxides on N-doped TiO 2 for CB/NO x synergistic degradation. CHEMOSPHERE 2023; 329:138613. [PMID: 37030352 DOI: 10.1016/j.chemosphere.2023.138613] [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: 08/28/2022] [Revised: 02/10/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
The synergistic degradation of VOCs and NOx that were emitted from the incineration of municipal and medical wastes by a single catalyst is challenging, due to the poor activity at low temperatures, and the SO2 poisoning on the active sites. Herein, N-doped TiO2 (N-TiO2) was used as the support for designing a highly efficient and stable catalyst system for CB/NOx synergistic degradation even in the presence of SO2. The prepared SbPdV/N-TiO2 catalyst, which presented excellent activity and tolerance to SO2 in the CBCO + SCR process, was investigated by a series of characterizations (such as XRD, TPD, XPS, H2-TPR and so on) as well as DFT calculations. The electronic structure of the catalyst was effectively modulated after N doping, resulting in effective charge flow between the catalyst surface and gas molecules. More importantly, the adsorption and deposition of sulfur species and reaction transient intermediates on active centers were restrained, while a new N adsorption center for NOx was provided. Abundant adsorption centers and superior redox properties ensured smooth CB/NOx synergistic degradation. The removal of CB mainly follows the L-H mechanism, while NOx elimination follows both E-R and L-H mechanisms. As a result, N doping provides a new approach to develop more advanced anti-SO2 poisoning CB/NOx synergistic catalytic removal systems for extensive applications.
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Affiliation(s)
- Guobo Li
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, Jiangsu, PR China
| | - Yaping Zhang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, Jiangsu, PR China
| | - Peng Wu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, Jiangsu, PR China
| | - Kai Shen
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, Jiangsu, PR China
| | - Shule Zhang
- School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Shipeng Ding
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, Jiangsu, PR China.
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Wei N, Zhao C, Hu X, Tong Z, Yun J, Jiang X, Liu C, Wang K, Zou Y, Chen Z. Elucidating the facet-dependent reactivity of CrMn catalyst for selective catalytic reduction of NO x with NH 3. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158881. [PMID: 36411606 DOI: 10.1016/j.scitotenv.2022.158881] [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: 07/14/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
The facet-dependent reactivity of CrMn catalysts was still unclear, hindering the further enhancement of their low-temperature SCR performance. Herein, the facet-dependent reactivity of CrMn1.5O4 catalyst for NH3-SCR of NOx was innovatively illustrated by numerous characterizations and density functional theory (DFT) calculations. Exposed (100) facet of CrMn1.5O4 catalyst exhibited best low-temperature SCR activity with ≥90 % NO conversion within 148-296 °C and 2.86 × 10-3 mol/(g·s) reaction rate within 160-240 °C. The characterizations revealed that (100) facet could induce the increase of BET specific area, electron transfer, concentration of Mn4+ and Oα, surface acidity, redox ability, NH3 and NOx adsorption/activation capacity. Subsequently, DFT calculations demonstrated that (100) facet exhibited the strongest affinity for NH3 and NO due to its unique 3O3c-Mn5c-2O4c bond and abundant charges transfer near the active adsorption sites, and Brønsted acid and oxygen vacancies were most easily formed on (100) facet. Furthermore, H2O formation as the rate determining step easily occurred on (100) facet. Eventually, we successfully improved the low-temperature SCR activity of CrMn1.5O4 catalyst by further tailoring highly active (100) facet from 0.754 to 0.865. This work provides the deeper understanding of facet-dependent reactivity and a good strategy to improve the catalytic activity of the catalysts.
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Affiliation(s)
- Ninghan Wei
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Cheng Zhao
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China
| | - Xiaomei Hu
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China
| | - Zhangfa Tong
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Junge Yun
- College of Environment and Resources, Xiangtan University, Xiangtan, 411105, PR China
| | - Xueying Jiang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Chengxian Liu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Keju Wang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Yun Zou
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China.
| | - Zhihang Chen
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China; College of Environment and Resources, Xiangtan University, Xiangtan, 411105, PR China.
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Ma N, Ru Y, Weng M, Chen L, Chen W, Dai Q. Synergistic mechanism of supported Mn-Ce oxide in catalytic ozonation of nitrofurazone wastewater. CHEMOSPHERE 2022; 308:136192. [PMID: 36041529 DOI: 10.1016/j.chemosphere.2022.136192] [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: 06/30/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
In this study, the catalytic materials of MnOx/γ-Al2O3, CeO2/γ-Al2O3, and MnxCe1-xO2/γ-Al2O3 for catalytic ozonation were synthesized. The catalysts were used in heterogeneous catalytic ozonation of the wastewater containing ntrofurazone (NFZ). The effects of the catalytic ozonation operational factors were systematically evaluated in terms of ozone dosing, catalyst dosing, initial NFZ concentration, and pH. The results showed that the catalytic activity of the MnxCe1-xO2/γ-Al2O3 was higher than that of the MnOx/γ-Al2O3 and CeO2/γ-Al2O3. The kinetics analysis revealed that bimetallic loading has a synergistic effect and the mechanism of this effect was investigated in the catalytic ozonation system. The catalysts were characterized by FESEM, EDS, XRD, XPS, IR, and BET. The characteristics of the catalysts revealed that Mn could alter the oxide species on the metal surface and interfere with the formation of CeO2 crystals, which led to smaller grains, enhanced adsorption oxygen, and greater specific surface area. The MnxCe1-xO2/γ-Al2O3 crystals could form a solid solution, which helps higher catalytic activity. This study adds to the understanding of the synergistic mechanism of the loaded Ce-Mn oxide catalysts in the heterogeneous catalytic ozonation system and provides a feasible method for degrading pharmaceutical wastewater.
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Affiliation(s)
- Nengwei Ma
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Yifan Ru
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Mili Weng
- College of Environmental and Resources Sciences, Zhejiang A&F University, Hangzhou, 311300, China.
| | - Lu Chen
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Wenqing Chen
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Qizhou Dai
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China.
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Guo RT, Qin B, Wei LG, Yin TY, Zhou J, Pan WG. Recent progress of low-temperature selective catalytic reduction of NOx with NH3 over manganese oxide-based catalysts. Phys Chem Chem Phys 2022; 24:6363-6382. [DOI: 10.1039/d1cp05557g] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective catalytic reduction with NH3 (NH3−SCR) was the most efficient approach to mitigate the emission of nitrogen oxides (NOx). Although the conventional manganese oxide-based catalyst had gradually become a kind...
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