Nanocatalysts for Air Purification

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Environmental Nanoscience and Nanotechnology".

Deadline for manuscript submissions: closed (20 June 2023) | Viewed by 5028

Special Issue Editor

Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
Interests: pollution control of VOCs via exploiting nanocatalysts

Special Issue Information

Dear Colleagues,

Volatile organic compounds (VOCs) are some of the main causes of severe environmental pollution, such as fine particulate matter (PM2.5) and ozone (O3). The catalytic degradation using nanocatalysts is a promising technology for the purification of these VOCs. This Special Issue focuses on the purification of odorous sulfur/nitrogen-containing VOCs or other odorous VOCs by using various types of nano/cluster/single-atom catalysts.

For this Special Issue, we invite contributions from leading groups in the field with the aim of providing a comprehensive and deep understanding of the current, state-of-the-art catalysts for the purification of odorous VOCs.

We look forward to receiving your contributions.

Dr. Jichang Lu
Guest Editor

Manuscript Submission Information

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Keywords

  • VOCs
  • catalytic degradation
  • odorous matters
  • nanocatalysts
  • cluster catalysts
  • single-atom catalysts

Published Papers (4 papers)

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Research

13 pages, 4229 KiB  
Article
Influence of Carbonization Conditions on Structural and Surface Properties of K-Doped Mo2C Catalysts for the Synthesis of Methyl Mercaptan from CO/H2/H2S
by Xiangqian Zheng, Tianhao Ai, Yuhong Hu, Zhizhi Xu, Yubei Li, Huan Jiang and Yongming Luo
Nanomaterials 2023, 13(18), 2602; https://doi.org/10.3390/nano13182602 - 21 Sep 2023
Viewed by 764
Abstract
The cooperative transition of sulfur-containing pollutants of H2S/CO/H2 to the high-value chemical methyl mercaptan (CH3SH) is catalyzed by Mo-based catalysts and has good application prospects. Herein, a series of Al2O3-supported molybdenum carbide catalysts with [...] Read more.
The cooperative transition of sulfur-containing pollutants of H2S/CO/H2 to the high-value chemical methyl mercaptan (CH3SH) is catalyzed by Mo-based catalysts and has good application prospects. Herein, a series of Al2O3-supported molybdenum carbide catalysts with K doping (denoted herein as K-Mo2C/Al2O3) are fabricated by the impregnation method, with the carbonization process occurring under different atmospheres and different temperatures between 400 and 600 °C. The CH4-K-Mo2C/Al2O3 catalyst carbonized by CH4/H2 at 500 °C displays unprecedented performance in the synthesis of CH3SH from CO/H2S/H2, with 66.1% selectivity and a 0.2990 g·gcat−1·h−1 formation rate of CH3SH at 325 °C. H2 temperature-programmed reduction, temperature-programmed desorption, X-ray diffraction and Raman and BET analyses reveal that the CH4-K-Mo2C/Al2O3 catalyst contains more Mo coordinatively unsaturated surface sites that are responsible for promoting the adsorption of reactants and the desorption of intermediate products, thereby improving the selectivity towards and production of CH3SH. This study systematically investigates the effects of catalyst carbonization and passivation conditions on catalyst activity, conclusively demonstrating that Mo2C-based catalyst systems can be highly selective for producing CH3SH from CO/H2S/H2. Full article
(This article belongs to the Special Issue Nanocatalysts for Air Purification)
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12 pages, 5793 KiB  
Article
Preparation of Ce-MnOx Composite Oxides via Coprecipitation and Their Catalytic Performance for CO Oxidation
by Junsheng Yang, Jie Li, Jiangang Kang, Wenkang Liu, Yijian Kuang, Hua Tan, Zhensen Yu, Liu Yang, Xuejin Yang, Kui Yu and Yiquan Fan
Nanomaterials 2023, 13(15), 2158; https://doi.org/10.3390/nano13152158 - 25 Jul 2023
Viewed by 946
Abstract
Ce-MnOx composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60–140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation [...] Read more.
Ce-MnOx composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60–140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation performance of CO was investigated using X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), H2 temperature programmed reduction (H2-TPR), CO-temperature programmed desorption (CO-TPD), and in situ infrared spectra. The experimental results reveal that under the same test conditions, the CO conversion rate of pure Mn3O4 reaches 95.4% at 170 °C. Additionally, at 140 °C, the Ce-MnOx series composite oxide catalyst converts CO at a rate of over 96%, outperforming single-phase Mn3O4 in terms of catalytic performance. With the decrement in Ce content, the performance of Ce-MnOx series composite oxide catalysts first increase and then decrease. The Ce MnOx catalyst behaves best when Ce:Mn = 1:1, with a CO conversion rate of 99.96% at 140 °C and 91.98% at 100 °C. Full article
(This article belongs to the Special Issue Nanocatalysts for Air Purification)
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29 pages, 8566 KiB  
Article
Oxidation of Methanol and Dichloromethane on TiO2-CeO2-CuO, TiO2-CeO2 and TiO2-CuO@VUKOPOR®A Ceramic Foams
by Lenka Matějová, Ivana Troppová, Satu Pitkäaho, Kateřina Pacultová, Dagmar Fridrichová, Ondřej Kania and Riitta Keiski
Nanomaterials 2023, 13(7), 1148; https://doi.org/10.3390/nano13071148 - 23 Mar 2023
Viewed by 1238
Abstract
The application-attractive form of TiO2, CeO2 and CuO-based open-cell foam supported catalysts was designed to investigate their catalytic performance in oxidation of two model volatile organic compounds—methanol and dichloromethane. TiO2-CeO2, TiO2-CuO and TiO2 [...] Read more.
The application-attractive form of TiO2, CeO2 and CuO-based open-cell foam supported catalysts was designed to investigate their catalytic performance in oxidation of two model volatile organic compounds—methanol and dichloromethane. TiO2-CeO2, TiO2-CuO and TiO2-CeO2-CuO catalysts as thin films were deposited on VUKOPOR®A ceramic foam using a reverse micelles-controlled sol-gel method, dip-coating and calcination. Three prepared catalytic foams were investigated via light-off tests in methanol and dichloromethane oxidation in the temperature range of 45–400 °C and 100–500 °C, respectively, at GHSV of 11, 600 h−1, which fits to semi-pilot/industrial conditions. TiO2-CuO@VUKOPOR®A foam showed the best catalytic activity and CO2 yield in methanol oxidation due to its low weak Lewis acidity, high weak basicity and easily reducible CuO species and proved good catalytic stability within 20 h test. TiO2-CeO2-CuO@VUKOPOR®A foam was the best in dichloromethane oxidation. Despite of its lower catalytic activity compared to TiO2-CeO2@VUKOPOR®A foam, its highly-reducible -O-Cu-Ce-O- active surface sites led to the highest CO2 yield and the highest weak Lewis acidity contributed to the highest HCl yield. This foam also showed the lowest amount of chlorine deposits. Full article
(This article belongs to the Special Issue Nanocatalysts for Air Purification)
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16 pages, 3237 KiB  
Article
Comparative Study of α- and β-MnO2 on Methyl Mercaptan Decomposition: The Role of Oxygen Vacancies
by Hong Su, Jiangping Liu, Yanan Hu, Tianhao Ai, Chenhao Gong, Jichang Lu and Yongming Luo
Nanomaterials 2023, 13(4), 775; https://doi.org/10.3390/nano13040775 - 19 Feb 2023
Cited by 1 | Viewed by 1726
Abstract
As a representative sulfur-containing volatile organic compounds (S-VOCs), CH3SH has attracted widespread attention due to its adverse environmental and health risks. The performance of Mn-based catalysts and the effect of their crystal structure on the CH3SH catalytic reaction have [...] Read more.
As a representative sulfur-containing volatile organic compounds (S-VOCs), CH3SH has attracted widespread attention due to its adverse environmental and health risks. The performance of Mn-based catalysts and the effect of their crystal structure on the CH3SH catalytic reaction have yet to be systematically investigated. In this paper, two different crystalline phases of tunneled MnO2 (α-MnO2 and β-MnO2) with the similar nanorod morphology were used to remove CH3SH, and their physicochemical properties were comprehensively studied using high-resolution transmission electron microscope (HRTEM) and electron paramagnetic resonance (EPR), H2-TPR, O2-TPD, Raman, and X-ray photoelectron spectroscopy (XPS) analysis. For the first time, we report that the specific reaction rate for α-MnO2 (0.029 mol g−1 h−1) was approximately 4.1 times higher than that of β-MnO2 (0.007 mol g−1 h−1). The as-synthesized α-MnO2 exhibited higher CH3SH catalytic activity towards CH3SH than that of β-MnO2, which can be ascribed to the additional oxygen vacancies, stronger surface oxygen migration ability, and better redox properties from α-MnO2. The oxygen vacancies on the catalyst surface provided the main active sites for the chemisorption of CH3SH, and the subsequent electron transfer led to the decomposition of CH3SH. The lattice oxygen on catalysts could be released during the reaction and thus participated in the further oxidation of sulfur-containing species. CH3SSCH3, S0, SO32−, and SO42− were identified as the main products of CH3SH conversion. This work offers a new understanding of the interface interaction mechanism between Mn-based catalysts and S-VOCs. Full article
(This article belongs to the Special Issue Nanocatalysts for Air Purification)
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