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Chen Z, Yin H, Wang C, Wang R, Peng Y, You C, Li J. New Insights on Competitive Adsorption of NO/SO 2 on TiO 2 Anatase for Photocatalytic NO Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9285-9292. [PMID: 34130451 DOI: 10.1021/acs.est.1c01749] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Here, we investigate competitive adsorption and photocatalytic reaction over TiO2@SiO2: NO conversion efficiency decreases by 29.1%, and the adsorption capacity decreases from 0.125 to 0.095 mmol/g due to the influence of SO2. According to identification and comparative analysis of the IR signal, SO2 has little effect on the NO conversion route and intermediates (adsorbed NO → nitrite → nitrate), but accelerates the deactivation of catalysts. The electronic interaction scheme from density functional theory (DFT) confirms that surface hydroxyls create an unsaturated coordination of neighboring Ti or O atoms, which is favorable for NO/SO2 adsorption on anatase (101). In addition, the lone pair electrons of N or S atoms prefer to be delocalized and form covalent bonds with active surface-O on the (101) facet with terminal hydroxyls. However, preadsorbed SO2 could offset the increase of hydroxyls and strongly inhibit NO adsorption, which is consistent with the result performance evaluation. A possible reaction mechanism characterized by oxygen vacancies and·O2- is proposed, while the essential reason of catalyst deactivation and regeneration is theoretically analyzed based on the experimental and DFT calculation.
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Affiliation(s)
- Zhen Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Haibo Yin
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Chizhong Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Rong Wang
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Changfu You
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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Wang H, Liu H, Chen Z, Veksha A, Lisak G, You C. Interaction between SO 2 and NO in their adsorption and photocatalytic conversion on TiO 2. CHEMOSPHERE 2020; 249:126136. [PMID: 32044609 DOI: 10.1016/j.chemosphere.2020.126136] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/17/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
The simultaneous adsorption and photocatalytic conversion of SO2 and NO on P25-TiO2 were studied. In particular, the interaction of SO2 and NO on each other's adsorption and photocatalytic oxidation was discussed. The adsorption of NO on P25 was negligible when comparing to that of SO2, while with the coexistence of NO and SO2 in flue gas, both the adsorption of SO2 and NO were improved. In the presence of water and oxygen, the photocatalytic oxidation efficiency of NO with an efficiency of >69% was observed on irradiated TiO2 surface, which lasted for at least 1000 min. Oxygen was found to have much more important effect than water on the photocatalytic oxidation of NO. In the presence of SO2 however, the photocatalytic process of NO was largely reshaped. The whole process was controlled by the photocatalytic oxidation of SO2. A dramatic efficiency decease (breakthrough of the catalyst bed) was observed for both NO and SO2 due to the catalyst deactivation caused by the poisoning of SO2 oxidation products. Before the breakthrough, the photocatalytic conversion efficiency of NO increased with increasing the SO2 concentration, which was mainly due to the improved NO adsorption in the presence of SO2.
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Affiliation(s)
- Haiming Wang
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore.
| | - Hanzi Liu
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China
| | - Zhen Chen
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China
| | - Andrei Veksha
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore
| | - Grzegorz Lisak
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Changfu You
- Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China.
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