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Li X, Li H, Huang Y, Cao J, Huang T, Li R, Zhang Q, Lee SC, Ho W. Exploring the photocatalytic conversion mechanism of gaseous formaldehyde degradation on TiO 2-x-OV surface. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127217. [PMID: 34879541 DOI: 10.1016/j.jhazmat.2021.127217] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/29/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
To understand the conversion mechanism of photocatalytic gaseous formaldehyde (HCHO) degradation, strontium (Sr)-doped TiO2-x-OV catalysts was designed and synthesized in this study, with comparable HCHO removal performance. Our results proved that foreign-element doping reduced Ti4+ to the lower oxidation state Ti(4- x)+, and that the internal charge kinetics was largely facilitated by the unbalanced electron distribution. Oxygen vacancies (OVs) were developed spontaneously to realize an electron-localized phenomenon in TiO2-x-OV, thereby boosting O2 adsorption and activation for the enhanced generation of reactive oxygen species (ROS). At the chemisorption stage, in-situ DRIFTS spectra and density functional theory calculation results revealed that surface adsorbed O2 (Oads) and lattice O (Olat) engaged in the isomerisation of HCHO to dioxymethylene (DOM) on TiO2-x-OV and TiO2, respectively. Time-resolved DRIFTS spectra under light irradiation revealed that the DOM was then converted to formate and thoroughly oxidized to CO2 and H2O in TiO2-x-OV. While bicarbonate byproducts were detected from DOM hydroxylation or possible side conversion of CO2 in TiO2, owing to insufficient consumption of surface hydroxyl. Our study enhances the understanding on the photocatalytic oxidation of HCHO, thereby promoting the practical application in indoor air purification.
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Affiliation(s)
- Xinwei Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Haiwei Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CIC-AEET), School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yu Huang
- State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Junji Cao
- State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Tingting Huang
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China
| | - Rong Li
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China
| | - Qian Zhang
- Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China
| | - Shun-Cheng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China.
| | - Wingkei Ho
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China; State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; State Key Laboratory of Marine Pollution, The City University of Hong Kong, Hong Kong, China.
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Lee JJ, Kim K, Kim KJ, Kim HJ, Lee YM, Shin TH, Han JW, Lee KT. In-situ exsolution of Ni nanoparticles to achieve an active and stable solid oxide fuel cell anode catalyst on A-site deficient La0.4Sr0.4Ti0.94Ni0.06O3-δ. J IND ENG CHEM 2021. [DOI: 10.1016/j.jiec.2021.07.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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