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Ao R, Pu T, Ma L, Dai Q, Yang J, Li W, Xie L, Guo Z. Understanding the effects of A-site Ag-doping on LaCoO 3 perovskite for NO oxidation: Structural and magnetic properties. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120160. [PMID: 38278120 DOI: 10.1016/j.jenvman.2024.120160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/01/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
The partial substitution of A-site in perovskites is a major strategy to enhance the catalytic oxidation activity. This study explores the use of silver (Ag) to partially replace the lanthanum (La) ion at the A-site in LaCoO3 perovskite, investigating the role of Ag in the ABO3 perovskite structure, elucidating the nitric oxide (NO) oxidation mechanism over La1-xAgxCoO3 (x = 0.1-0.5) perovskites. La0.7Ag0.3CoO3 with an Ag-doping amount of 0.3, exhibited the highest NO oxidation activity of 88.5% at 275 °C. Characterization results indicated that Ag substitution enhanced the perovskite, maintaining its original phase structure, existing in the form of a mixture of Ag0 and Ag+ in the La1-xAgxCoO3 (x = 0.1-0.5) perovskites. Notably, Ag substitution improved the specific surface area, reduction performance, Co3+, and surface adsorption oxygen content. Additionally, the study investigated the relationship between magnetism and NO oxidation from a magnetism perspective. Ag-doping strengthened the magnetism of La-Ag perovskite, resulting in stronger adsorption of paramagnetic NO. This study elucidated the NO oxidation mechanism over La-Ag perovskite, considering structural and magnetic properties, providing valuable insights for the subsequent development and industrial application of high oxidation ability perovskite catalysts.
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Affiliation(s)
- Ran Ao
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, PR China
| | - Tao Pu
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, PR China
| | - Liping Ma
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, 650500, PR China.
| | - Quxiu Dai
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, 650500, PR China
| | - Jie Yang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, 650500, PR China
| | - Wengang Li
- Kunming University of Science and Technology Design & Research Institute Co., Ltd., Kunming, Yunnan, 650500, PR China
| | - Longgui Xie
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, 650500, PR China
| | - Zhiying Guo
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, Yunnan, 661199, PR China.
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Yang J, Zhao L, Zhou T, Ma S, Wang X. Catalytic Oxidation Activity of NO over Mullite-Supported Amorphous Manganese Oxide Catalyst. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16103821. [PMID: 37241448 DOI: 10.3390/ma16103821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 05/10/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023]
Abstract
Nitric oxide (NO) can pose a severe threat to human health and the environment. Many catalytic materials that contain noble metals can oxidize NO into NO2. Therefore, the development of a low-cost, earth-abundant, and high-performance catalytic material is essential for NO removal. In this study, mullite whiskers on a micro-scale spherical aggregate support were obtained from high-alumina coal fly ash using an acid-alkali combined extraction method. Microspherical aggregates and Mn(NO3)2 were used as the catalyst support and the precursor, respectively. A mullite-supported amorphous manganese oxide (MSAMO) catalyst was prepared by impregnation and calcination at low temperatures, in which amorphous MnOx is evenly dispersed on the surface and inside of aggregated microsphere support. The MSAMO catalyst, with a hierarchical porous structure, exhibits high catalytic performance for the oxidation of NO. The MSAMO catalyst, with a 5 wt% MnOx loading, presented satisfactory NO catalytic oxidation activity at 250 °C, with an NO conversion rate as high as 88%. Manganese exists in a mixed-valence state in amorphous MnOx, and Mn4+ provides the main active sites. The lattice oxygen and chemisorbed oxygen in amorphous MnOx participate in the catalytic oxidation of NO into NO2. This study provides insights into the effectiveness of catalytic NO removal in practical industrial coal-fired boiler flue gas. The development of high-performance MSAMO catalysts represents an important step towards the production of low-cost, earth-abundant, and easily synthesized catalytic oxidation materials.
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Affiliation(s)
- Jianlin Yang
- College of Materials Science and Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Lu Zhao
- College of Materials Science and Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Tianran Zhou
- School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Shuhua Ma
- CAS Key Laboratory for Green Processes and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Wang
- CAS Key Laboratory for Green Processes and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
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