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Liang X, Wang L, Wen T, Liu H, Zhang J, Liu Z, Zhu C, Long C. Mesoporous poorly crystalline α-Fe 2O 3 with abundant oxygen vacancies and acid sites for ozone decomposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:150161. [PMID: 34517313 DOI: 10.1016/j.scitotenv.2021.150161] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/27/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
In this work, mesoporous poorly crystalline hematite (α-Fe2O3) was prepared using mesoporous silica (KIT-6) functionalized with 3-[(2-aminoethyl)amino]propyltrimethoxysilane as a hard template (SMPC-α-Fe2O3). The disordered atomic arrangement structure of SMPC-α-Fe2O3 promoted the formation of oxygen vacancies, which was confirmed using X-ray photoelectron spectroscopy (XPS), O2-temperature-programmed desorption (TPD), H2-temperature-programmed reduction (TPR), and in situ diffuse reflectance infrared Fourier transform (DRIFT) analyses. Density functional theory calculations (DFT) also proved that reducing the crystallinity of α-Fe2O3 decreased the formation energy of oxygen vacancies. TPD and in situ DRIFT analyses of NH3 adsorption suggested that the surface acidity of SMPC-α-Fe2O3 was considerably higher than those of mesoporous poorly crystalline α-Fe2O3 (MPC-α-Fe2O3) and highly crystalline α-Fe2O3 (HC-α-Fe2O3). The oxygen vacancies and acid sites formed on α-Fe2O3 surface are beneficial for ozone (O3) decomposition. Compared with MPC-α-Fe2O3 and HC-α-Fe2O3, SMPC-α-Fe2O3 exhibited a higher removal efficiency for 200-ppm O3 at a space velocity of 720 L g-1 h-1 at 25 ± 2 °C under dry conditions. Additionally, in situ DRIFT and XPS results suggested that the accumulation of peroxide (O22-) and the conversion of O22- to lattice oxygen over the oxygen vacancies caused catalyst deactivation. However, O22- could be desorbed completely by continuous N2 purging at approximately 350 °C. This study provides significant insights for developing highly active α-Fe2O3 catalysts for O3 decomposition.
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Affiliation(s)
- Xiaoshan Liang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Lisha Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Tiancheng Wen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Huijuan Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Jian Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Zhu Liu
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Chengzhang Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Chao Long
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China; Quanzhou Institute for Environmental Protection Industry, Nanjing University, Beifeng Road, Quanzhou 362000, China.
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Berro Y, Badawi M, El Haj Hassan F, Kassir M, Tielens F. Water-silanol interactions on the amorphous silica surface: A dispersion-corrected DFT investigation. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Tielens F, Gierada M, Handzlik J, Calatayud M. Characterization of amorphous silica based catalysts using DFT computational methods. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.03.062] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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