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Chen X, Wang X, Jia Z, Yang C, Liu Z, Wei Y, Wang M, Liang M. Weakened Mn-O bond in Mn-Ce catalysts through K doping induced oxygen activation for boosting benzene oxidation at low temperatures. J Colloid Interface Sci 2024; 666:88-100. [PMID: 38583213 DOI: 10.1016/j.jcis.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 03/19/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
K-doped Mn-Ce solid solution catalysts were synthesized using a combination of coprecipitation and hydrothermal methods, demonstrating excellent performance in benzene oxidation. The catalyst K1Ce5Mn5 exhibited comparable activity to noble metal catalysts, achieving a 90 % benzene conversion at approximately 194 ℃. Durable tests under dry and moist conditions revealed that the catalyst could maintain its activity for 50 h at 218 ℃ and 236 ℃, respectively. Characterization results indicated that the catalyst's enhanced activity resulted from the weakened Mn-O bonding caused by the introduction of K+, facilitating the activation of oxygen and its involvement in the reaction. CeOx, the main crystalline phase of Mn-Ce solid solutions, provided abundant oxygen vacancies for capturing and activating oxygen molecules for the weakened Mn-O structures. This conclusion was further supported by partial density of state analysis from density functional theory computations, revealing that the introduction of K+ weakened the orbital hybridization of Mn3d and O2p. Finally, in situ diffuse reflectance infrared Fourier-transform spectroscopy (in situ DRIFTS) studies on Ce5Mn5 and K1Ce5Mn5 catalysts suggested that the introduction of K+ promoted the conversion of adsorbed benzene. Furthermore, intermediate products were transformed more rapidly for K1Ce5Mn5 compared to Ce5Mn5.
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Affiliation(s)
- Xi Chen
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China; Shanxi Key Laboratory of Compound Air Pollutions Identification and Control, Jinzhong 030600, China; Shanxi Institute of Eco-Environmental Planning and Technology, Taiyuan 030009, China
| | - Xiaoyan Wang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China
| | - Ziliang Jia
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China
| | - Chao Yang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China; Shanxi Key Laboratory of Compound Air Pollutions Identification and Control, Jinzhong 030600, China
| | - Zhihong Liu
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China
| | - Yuexing Wei
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China
| | - Mengxue Wang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China
| | - Meisheng Liang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, China; Shanxi Key Laboratory of Compound Air Pollutions Identification and Control, Jinzhong 030600, China.
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