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Huang S, Wang Q, Shan Y, Shi X, Liu Z, He H. Effects of Si/Al Ratio on Passive NO x Adsorption Performance over Pd/Beta Zeolites. Molecules 2023; 28:molecules28083501. [PMID: 37110735 PMCID: PMC10145102 DOI: 10.3390/molecules28083501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
In the current article, the effect of Si/Al ratio on the NOx adsorption and storage capacity over Pd/Beta with 1 wt% Pd loading was investigated. The XRD, 27Al NMR and 29Si NMR measurements were used to determine the structure of Pd/Beta zeolites. XAFS, XPS, CO-DRIFT, TEM and H2-TPR were used to identify the Pd species. The results showed that the NOx adsorption and storage capacity on Pd/Beta zeolites gradually decreased with the increase of Si/Al ratio. Pd/Beta-Si (Si-rich, Si/Al~260) rarely has NOx adsorption and storage capacity, while Pd/Beta-Al (Al-rich, Si/Al~6) and Pd/Beta-C (Common, Si/Al~25) exhibit excellent NOx adsorption and storage capacity and suitable desorption temperature. Pd/Beta-C has slightly lower desorption temperature compared to Pd/Beta-Al. The NOx adsorption and storage capacity increased for Pd/Beta-Al and Pd/Beta-C by hydrothermal aging treatment, while the NOx adsorption and storage capacity on Pd/Beta-Si had no change.
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Affiliation(s)
- Shasha Huang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
- Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Qiang Wang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
- Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yulong Shan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyan Shi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhongqi Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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Khivantsev K, Jaegers NR, Aleksandrov HA, Song I, Pereira-Hernandez XI, Engelhard MH, Tian J, Chen L, Motta Meira D, Kovarik L, Vayssilov GN, Wang Y, Szanyi J. Single Ru(II) Ions on Ceria as a Highly Active Catalyst for Abatement of NO. J Am Chem Soc 2023; 145:5029-5040. [PMID: 36812067 DOI: 10.1021/jacs.2c09873] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Atom trapping leads to catalysts with atomically dispersed Ru1O5 sites on (100) facets of ceria, as identified by spectroscopy and DFT calculations. This is a new class of ceria-based materials with Ru properties drastically different from the known M/ceria materials. They show excellent activity in catalytic NO oxidation, a critical step that requires use of large loadings of expensive noble metals in diesel aftertreatment systems. Ru1/CeO2 is stable during continuous cycling, ramping, and cooling as well as the presence of moisture. Furthermore, Ru1/CeO2 shows very high NOx storage properties due to formation of stable Ru-NO complexes as well as a high spill-over rate of NOx onto CeO2. Only ∼0.05 wt % of Ru is required for excellent NOx storage. Ru1O5 sites exhibit much higher stability during calcination in air/steam up to 750 °C in contrast to RuO2 nanoparticles. We clarify the location of Ru(II) ions on the ceria surface and experimentally identify the mechanism of NO storage and oxidation using DFT calculations and in situ DRIFTS/mass spectroscopy. Moreover, we show excellent reactivity of Ru1/CeO2 for NO reduction by CO at low temperatures: only 0.1-0.5 wt % of Ru is sufficient to achieve high activity. Modulation-excitation in situ infrared and XPS measurements reveal the individual elementary steps of NO reduction by CO on an atomically dispersed Ru ceria catalyst, highlighting unique properties of Ru1/CeO2 and its propensity to form oxygen vacancies/Ce+3 sites that are critical for NO reduction, even at low Ru loadings. Our study highlights the applicability of novel ceria-based single-atom catalysts to NO and CO abatement.
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Affiliation(s)
- Konstantin Khivantsev
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Nicholas R Jaegers
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Hristiyan A Aleksandrov
- Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1, J. Bourchier boulevard, 1126 Sofia, Bulgaria
| | - Inhak Song
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | | | - Mark H Engelhard
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Jinshu Tian
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Linxiao Chen
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Debora Motta Meira
- Canadian Light Source: Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Libor Kovarik
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - Georgi N Vayssilov
- Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1, J. Bourchier boulevard, 1126 Sofia, Bulgaria
| | - Yong Wang
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
| | - János Szanyi
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352 United States
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Li Y, Chen D, Xu X, Wang X, Kang R, Fu M, Guo Y, Chen P, Li Y, Ye D. Cold-Start NO x Mitigation by Passive Adsorption Using Pd-Exchanged Zeolites: From Material Design to Mechanism Understanding and System Integration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3467-3485. [PMID: 36802541 DOI: 10.1021/acs.est.2c06207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
It remains a major challenge to abate efficiently the harmful nitrogen oxides (NOx) in low-temperature diesel exhausts emitted during the cold-start period of engine operation. Passive NOx adsorbers (PNA), which could temporarily capture NOx at low temperatures (below 200 °C) and release the stored NOx at higher temperatures (normally 250-450 °C) to downstream selective catalytic reduction unit for complete abatement, hold promise to mitigate cold-start NOx emissions. In this review, recent advances in material design, mechanism understanding, and system integration are summarized for PNA based on palladium-exchanged zeolites. First, we discuss the choices of parent zeolite, Pd precursor, and synthetic method for the synthesis of Pd-zeolites with atomic Pd dispersions, and review the effect of hydrothermal aging on the properties and PNA performance of Pd-zeolites. Then, we show how different experimental and theoretical methodologies can be integrated to gain mechanistic insights into the nature of Pd active sites, the NOx storage/release chemistry, as well as the interactions between Pd and typical components/poisons in engine exhausts. This review also gathers several novel designs of PNA integration into modern exhaust after-treatment systems for practical application. At the end, we discuss the major challenges, as well as important implications, for the further development and real application of Pd-zeolite-based PNA in cold-start NOx mitigation.
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Affiliation(s)
- Ying Li
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Dongdong Chen
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Xin Xu
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Xinyu Wang
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Running Kang
- Department of Chemical and Metallurgical Engineering, School of Chemical Engineering, Aalto University, 02150 Espoo, Finland
| | - Mingli Fu
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Yanbing Guo
- Institute of Environmental and Applied Chemistry, College of Chemistry, Central China Normal University, 430079 Wuhan, China
| | - Peirong Chen
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
| | - Yongdan Li
- Department of Chemical and Metallurgical Engineering, School of Chemical Engineering, Aalto University, 02150 Espoo, Finland
| | - Daiqi Ye
- National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China
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Tracking Structural Deactivation of H-Ferrierite Zeolite Catalyst During MTH with XRD. Top Catal 2023. [DOI: 10.1007/s11244-023-01780-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
AbstractWe used the methanol-to-hydrocarbon (MTH) reaction as a shape-selective model reaction to investigate coke formation in zeolite H-Ferrierite. Despite being a 2D topology in terms of channel propagation, the FER framework displays a lattice expansion in all three dimensions of space upon deactivation. Therefore, the volume of the unit cell is an excellent X-Ray diffraction (XRD) descriptor for the catalyst deactivation. A model with dummy atoms added, also proved to be an accurate approach to measure the amount of internal coke and/or water inside the pore network correlated with thermogravimetric analysis results. While the catalyst deactivation of the H-Ferrerite during the MTH was fast, a comparably long induction period was observed. We were able to track such fast deactivation with the aforementioned descriptors by means of an operando XRD study by a standard laboratory diffractometer.
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Cai J, Zhao H, Li X, Jing G, Schwank JW. Improving the hydrothermal stability of Pd/SSZ-13 for low-temperature NO adsorption: promotional effect of the Mg 2+ co-cation. REACT CHEM ENG 2023. [DOI: 10.1039/d3re00024a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Insufficient hydrothermal stability is an issue that restricts application of Pd/SSZ-13 for low-temperature NO adsorption from vehicle emissions.
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Affiliation(s)
- Jinhuang Cai
- Department of Environmental Science & Engineering, College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, China
| | - Huawang Zhao
- Department of Environmental Science & Engineering, College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, China
| | - Xiang Li
- Department of Chemical and Metallurgical Engineering, School of Chemical Engineering, Aalto University, Espoo 02150, Finland
| | - Guohua Jing
- Department of Environmental Science & Engineering, College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, China
| | - Johannes W. Schwank
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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