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Yan J, Liu P, Li J, Huang H, Song W. Structure and Electron Engineering for Nitrate Electrocatalysis to Ammonia: Identification and Modification of Active Sites in Spinel Oxides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308617. [PMID: 37985367 DOI: 10.1002/smll.202308617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/19/2023] [Indexed: 11/22/2023]
Abstract
Cobalt spinel oxides, which consist of tetrahedral site (AO4) and octahedral site (BO6), are a potential group of transition metal oxides (TMO) for electrocatalytic nitrate reduction reactions to ammonia (NRA). Identifying the true active site in spinel oxides is crucial to designing advanced catalysts. This work reveals that the CoO6 site is the dominant site for NRA through the site substitution strategy. The suitable electronic configuration of Co at the octahedral site leads to a stronger interaction between the Co d-orbital and the O p-orbital in O-containing intermediates, resulting in a high-efficiency nitrate-to-ammonia reduction. Furthermore, the substitution of metallic elements at the AO4 site can affect the charge density at the BO6 site via the structure of A-O-B. Thereafter, Ni and Cu are introduced to replace the tetrahedral site in spinel oxides and optimize the electronic structure of CoO6. As a result, NiCo2O4 exhibits the best activity for NRA with an outstanding yield of NH3 (15.49 mg cm-2 h-1) and FE (99.89%). This study introduces a novel paradigm for identifying the active site and proposes an approach for constructing high-efficiency electrocatalysts for NRA.
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Affiliation(s)
- Jianyue Yan
- College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Peng Liu
- College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Jiawen Li
- College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Hao Huang
- Department of Microsystems, University of South-Eastern Norway, Borre, 3184, Norway
| | - Wenbo Song
- College of Chemistry, Jilin University, Changchun, 130012, P. R. China
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Heterogeneous Activation of Peroxymonosulfate by a Spinel CoAl2O4 Catalyst for the Degradation of Organic Pollutants. Catalysts 2022. [DOI: 10.3390/catal12080847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Bimetallic catalysts have significantly contributed to the chemical community, especially in environmental science. In this work, a CoAl2O4 spinel bimetal oxide was synthesized by a facile co-precipitation method and used for the degradation of organic pollutants through peroxymonosulfate (PMS) activation. Compared with Co3O4, the as-prepared CoAl2O4 possesses a higher specific surface area and a larger pore volume, which contributes to its becoming increasingly conducive to the degradation of organic pollutants. Under optimal conditions (calcination temperature: 500 °C, catalyst: 0.1 g/L, and PMS: 0.1 g/L), the as-prepared CoAl2O4 catalyst could degrade over 99% of rhodamine B (RhB) at a degradation rate of 0.048 min−1, which is 2.18 times faster than Co3O4 (0.022 min−1). The presence of Cl− could enhance RhB degradation in the CoAl2O4/PMS system, while HCO3− and CO32− inhibit RhB degradation. Furthermore, the considerable reusability and universality of CoAl2O4 were testified. Through quenching tests, 1O2 and SO4•− were identified as the primary reactive species in RhB degradation. The toxicity evaluation verified that the degraded solution exhibited lower biological toxicity than the initial RhB solution. This study provides new prospects in the design of cost-effective and stable cobalt-based catalysts and promotes the application of PMS-based advanced oxidation processes for refractory wastewater treatment.
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Zhou M, Liu K, Peng Q, Jiang K, Tang X, Zhang Y, Xing J. Long-acting CoAl 2O 4 spinel catalyst developed on activated alumina pellets by facile synthesis to activate peroxymonosulfate: Controllable cobalt leaching and environmental adaptability. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 310:114702. [PMID: 35184008 DOI: 10.1016/j.jenvman.2022.114702] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/21/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
A novel composite catalyst prepared by fixing cobalt aluminate (CoAl2O4) spinel on formed alumina carrier by impregnation-calcination route is reported, which can be used to efficiently activate peroxymonosulfate (PMS) to degrade p-nitrophenol (PNP). The internal laws of phase composition and preparation conditions are explored in detail, and the results show that the introduction of additional aluminum ions in the preparation process changes the coordination environment and the electronic state of cobalt ions, which leads to the transformation of spinel/inverted spinel in the composition, and further affects the activity and stability of the catalyst. The selected CoAl-Aaps-600 catalyst has high CoAl2O4 content, showing good cycle performance and low cobalt leaching, and has great catalytic degradation performance at different temperatures and a wide pH range. Most notably, a fixed bed reactor packed with 20 g of CoAl-Aaps-600 exhibits excellent capacity to continuously treat 60 L of PNP solution with acceptable PNP removal ratio and low cobalt leaching content. Sulfate radical and singlet oxygen are identified as the main reactive oxygen species produced in CoAl-Aaps-600/PMS system, and the reaction mechanism is reasonably inferred. This work provides a potential application material and process for the treatment of continuous organic wastewater.
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Affiliation(s)
- Muyang Zhou
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
| | - Kun Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China.
| | - Qian Peng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
| | - Kun Jiang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
| | - Xuekun Tang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
| | - Yingjie Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
| | - Jiajie Xing
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Key Laboratory of Mineral Materials and Application, Central South University, Changsha, 410083, China
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