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Yang Y, Li J, Xiao Z, Yun Y, Zhu M, Yang J. Space-confined manganese oxides nanosheets for efficient catalytic decomposition of ozone. CHEMOSPHERE 2024; 358:142113. [PMID: 38657694 DOI: 10.1016/j.chemosphere.2024.142113] [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: 01/03/2024] [Revised: 03/09/2024] [Accepted: 04/21/2024] [Indexed: 04/26/2024]
Abstract
Ground-level ozone has long posed a substantial menace to human well-being and the ecological milieu. The widely reported manganese-based catalysts for ozone decomposition still facing the persisting issues encompass inefficiency and instability. To surmount these challenges, we developed a mesoporous silica thin films with perpendicular nanochannels (SBA(⊥)) confined Mn3O4 catalyst (Mn3O4@SBA(⊥)). Under a weight hourly space velocity (WHSV) of 500,000 mL g-1 h-1, the Mn3O4@SBA(⊥) catalyst exhibited 100% ozone decomposition efficiency in 5 h and stability across a wide humidity range, which exceed the performance of bulk Mn3O4 and Mn3O4 confine in commonly reported SBA-15. Rapidly decompose 20 ppm O3 to a safety level below 100 μg m-3 in the presence of dust in smog chamber (60 × 60 × 60 cm) was also realized. This prominent catalytic performance can be attributed to the unique confined structure engenders the highly exposed active sites, facilitate the reactant-active sites contact and impeded the water accumulation on the active sites. This work offers new insights into the design of confined structure catalysts for air purification.
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Affiliation(s)
- Yunjun Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou, 511443, PR China
| | - Jialin Li
- Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou, 511443, PR China
| | - Zhijian Xiao
- Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou, 511443, PR China
| | - Yang Yun
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi, 030006, PR China.
| | - Mingshan Zhu
- Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou, 511443, PR China
| | - Jingling Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, College of Environment and Climate, Jinan University, Guangzhou, 511443, PR China.
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2
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Li H, Wang W, Xu J, Wang A, Wan X, Yang L, Zhao H, Shan Q, Zhao C, Sun S, Wang W. Mn-Based Mullites for Environmental and Energy Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312685. [PMID: 38618925 DOI: 10.1002/adma.202312685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 03/26/2024] [Indexed: 04/16/2024]
Abstract
Mn-based mullite oxides AMn2O5 (A = lanthanide, Y, Bi) is a novel type of ternary catalyst in terms of their electronic and geometric structures. The coexistence of pyramid Mn3+-O and octahedral Mn4+-O makes the d-orbital selectively active toward various catalytic reactions. The alternative edge- and corner-sharing stacking configuration constructs the confined active sites and abundant active oxygen species. As a result, they tend to show superior catalytic behaviors and thus gain great attention in environmental treatment and energy conversion and storage. In environmental applications, Mn-based mullites have been demonstrated to be highly active toward low-temperature oxidization of CO, NO, volatile organic compounds (VOCs), etc. Recent research further shows that mullites decompose O3 and ozonize VOCs from -20 °C to room temperature. Moreover, mullites enhance oxygen reduction reactions (ORR) and sulfur reduction reactions (SRR), critical kinetic steps in air-battery and Li-S batteries, respectively. Their distinctive structures also facilitate applications in gas-sensitive sensing, ionic conduction, high mobility dielectrics, oxygen storage, piezoelectricity, dehydration, H2O2 decomposition, and beyond. A comprehensive review from basic physicochemical properties to application certainly not only gains a full picture of mullite oxides but also provides new insights into designing heterogeneous catalysts.
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Affiliation(s)
- Huan Li
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Wanying Wang
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Jinchao Xu
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Ansheng Wang
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Xiang Wan
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Liyuan Yang
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Haojun Zhao
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Qingyu Shan
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Chunning Zhao
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Shuhui Sun
- Institute National de la Recherche Scientifique (INRS), Centre Énergie Matériaux Télécommunications, Québec J3×1P7, Varennes, Canada
| | - Weichao Wang
- Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
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Sun X, Yang S, Liu X, Qiao Y, Liu Z, Li X, Pan J, Liu H, Wang L. The enhancement of benzene total oxidation over Ru xCeO 2 catalysts at low temperature: The significance of Ru incorporation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:165574. [PMID: 37474046 DOI: 10.1016/j.scitotenv.2023.165574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/06/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023]
Abstract
Catalytic oxidation is considered to be the most efficient technology for eliminating benzene from waste gas. The challenge is the reduction of the catalytic reaction temperature for the deep oxidation of benzene. Here, highly efficient RuxCeO2 catalysts were utilized to turn the number of surface oxygen vacancies and Ce-O-Ru bonds via a one-step hydrothermal method, resulting in a preferable low-temperature reducibility for the total oxidation of benzene. The T50 of the Ru0.2CeO2 catalyst for benzene oxidation was 135 °C, which was better than that of pristine CeO2 (239 °C) and 0.2Ru/CeO2 (190 °C). The superior performance of Ru0.2CeO2 was attributed to its large surface area (approximately 114.23 m2·g-1), abundant surface oxygen vacancies, and Ce-O-Ru bonds. The incorporation of Ru into the CeO2 lattice could effectively facilitate the destruction of the CeO bond and the facile release of lattice oxygen, inducing the generation of surface oxygen vacancies. Meanwhile, the bridging action of Ce-O-Ru bonds accelerated electron transfer and lattice oxygen transportation, which had a synergistic effect with surface oxygen vacancies to reduce the reaction temperature. The Ru0.2CeO2 catalyst also exhibited high catalytic stability, water tolerance, and impact resistance in terms of benzene abatement. Using in situ infrared spectroscopy, it was demonstrated that the Ru0.2CeO2 catalyst can effectively enhance the accumulation of maleate species, which are key intermediates for benzene ring opening, thereby enhancing the deep oxidation of benzene.
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Affiliation(s)
- Xiaoxia Sun
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Shu Yang
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
| | - Xin Liu
- Institute of Green Chemistry and Chemical Technology, School of Chemistry & Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Yarui Qiao
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Zhilou Liu
- School of Metallurgical Engineering, JiangXi University of Science and Technology, Ganzhou 341000, PR China
| | - Xinxin Li
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Jingwen Pan
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Hui Liu
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Lei Wang
- Key Laboratory of Eco-chemical Engineering, Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and Technology, Qingdao University of Science and Technology, Qingdao 266042, PR China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
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Wang F, Zheng Y, Zhu H, Wu T. Screening of MnO 2 with desired facet and its behavior in highly selective adsorption of aqueous Pb (II): Theoretical and experimental studies. CHEMOSPHERE 2023:139239. [PMID: 37379975 DOI: 10.1016/j.chemosphere.2023.139239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/29/2023] [Accepted: 06/14/2023] [Indexed: 06/30/2023]
Abstract
In this study, Density Functional Theory (DFT) calculations and experimental methods were used to evaluate MnO2 with 5 different facets for their selective adsorption of Pb (II) from wastewater containing Cd (II), Cu (II), Pb (II), and Zn (II). The DFT calculations were used to screen the selective adsorption capability of the facets and demonstrated that the MnO2 (3 1 0) facet has an excellent performance in selective adsorption of Pb (II) among all facets. The validity of DFT calculations was verified by comparing with the experimental results. MnO2 with different facets was prepared in a controlled manner and the characterizations confirmed that the lattice indices of the fabricated MnO2 have the desired facets. Adsorption performance experiments illustrated a high adsorption capacity (320.0 mg/g) on the (3 1 0) facet MnO2. The selectivity of adsorption of Pb (II) was 3-32 times greater than that of the other coexisting ions, i.e., Cd (II), Cu (II), and Zn (II)), which is consistent with results of the DFT calculations. Furthermore, DFT calculations of the adsorption energy, charge density difference, and projected density of states (PDOS) showed that the adsorption of Pb (II) on the MnO2 (3 1 0) facet is non-activated chemisorption. This study shows that it is feasible to use DFT calculations to quickly screen suitable adsorbents for environmental applications.
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Affiliation(s)
- Fan Wang
- New Materials Institute, University of Nottingham, Ningbo 315100, China; Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yueying Zheng
- New Materials Institute, University of Nottingham, Ningbo 315100, China; Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Huiwen Zhu
- New Materials Institute, University of Nottingham, Ningbo 315100, China; Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Tao Wu
- New Materials Institute, University of Nottingham, Ningbo 315100, China; Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China; Key Laboratory of Carbonaceous Wastes Processing and Process Intensification of Zhejiang Province, Ningbo 315100, China.
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5
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Surface Modification of GdMn2O5 for Catalytic Oxidation of Benzene via a Mild A-Site Sacrificial Strategy. Catalysts 2022. [DOI: 10.3390/catal12101267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Thermal catalytic oxidation technology is an effective way to eliminate refractory volatile organic pollutants, such as Benzene. Nevertheless, a high reaction temperature is usually an obstacle to practical application. Here, GdMn2O5 mullite (GMO-H) catalyst with disordered surface Gd-deficient and oxygen-vacancy-rich concentrations was synthesized via a controllable low-temperature acid-etching route. Results show that the preferentially broken Gd-O bond is conducive to exposing more Mn-Mn active sites, which Gd species covered. The affluent surface oxygen vacancies supply sufficient adsorption sites for oxygen molecules, facilitating the oxygen cycles during Benzene catalytic oxidation. Furthermore, surface exposed Mn3+ species were oxidized to Mn4+, which is beneficial to increase catalytic activity at a lower temperature. Compared with the conventional GdMn2O5, the reaction temperature for removing 90% Benzene over GMO-H was dropped from 405 to 310 °C with WHSV of 30,000 mL g−1 h−1. Significantly, during a 72 h catalytic test, the catalytic activity remains constant at 90% of the Benzene removal at 300 °C, indicating excellent activity stability. This work reported an efficient approach to preparing manganese-base mullite thermal catalyst, providing insight into the catalytic oxidation of Benzene.
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Yang Y, Fu W, Chen X, Chen L, Hou C, Tang T, Zhang X. Ceramic nanofiber membrane anchoring nanosized Mn 2O 3 catalytic ozonation of sulfamethoxazole in water. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129168. [PMID: 35617732 DOI: 10.1016/j.jhazmat.2022.129168] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Catalytic ceramic nanofiber membranes (Mn@CNMs) were prepared by anchoring Mn2O3 nanoparticles on the pits of attapulgite (APT) nanofibers via an impregnation and in-situ precipitation method. An integrated catalytic ozonation/membrane filtration process applying Mn@CNM was employed to degrade sulfamethoxazole (SMX) and the removal achieved up to 81.3% during a 7-h continuous filtration. The reactive oxygen species (ROS) quenching and radical detection experiments were conducted to determine the contribution of 1O2, ·OH and O2·- towards the catalytic degradation of SMX. Moreover, Mn@CNM exhibited wide applicability for real water matrix and the total removal of various kinds of emerging contaminants in real hospital wastewater reached up to 98.5%. The excellent performances of Mn@CNM were attributed to the nano-confinement effect in the membrane layer. First, anchoring Mn2O3 nanoparticles on the pits of the APT surface suppressed the growth and aggregation of nanosized Mn2O3, providing abundant reactive sites for catalytic ozonation. Second, the interlaced APT nanofibers formed nano-sized network structures, where ROS and SMX were confined in close vicinity and ROS have more chances to attack SMX. This work provides a promising strategy for the preparation of catalytic ceramic membrane with high catalytic efficiency for degradation of emerging contaminants in water.
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Affiliation(s)
- Yulong Yang
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; School of Environment, Tsinghua University, Beijing 100083, China
| | - Wanyi Fu
- School of Environment, Nanjing University, Nanjing 210023, China.
| | - Xixi Chen
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Li Chen
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; School of Environment, Tsinghua University, Beijing 100083, China
| | - Congyu Hou
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; School of Environment, Tsinghua University, Beijing 100083, China
| | - Tianhao Tang
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Xihui Zhang
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; School of Environment, Tsinghua University, Beijing 100083, China.
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Vikrant K, Kim KH, Dong F, Heynderickx PM, Boukhvalov DW. Low-temperature oxidative removal of gaseous formaldehyde by an eggshell waste supported silver-manganese dioxide bimetallic catalyst with ultralow noble metal content. JOURNAL OF HAZARDOUS MATERIALS 2022; 434:128857. [PMID: 35429758 DOI: 10.1016/j.jhazmat.2022.128857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/01/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
Under dark/low temperature (DLT) conditions, the oxidative removal of gaseous formaldehyde (FA) was studied using eggshell waste supported silver (Ag)-manganese dioxide (MnO2) bimetallic catalysts. To assess the synergistic effects between the two different metals, 0.03%-Ag-(0.5-5%)-MnO2/Eggshell catalysts were prepared and employed for DLT-oxidation of FA. The steady-state FA oxidation reaction rate (mmol g-1 h-1), when measured using 100 ppm FA at 80 °C (gas hourly space velocity (GHSV) of 5308 h-1), varied as follows: Ag-1.5%-MnO2/Eggshell-R (9.4) > Ag-3%-MnO2/Eggshell-R (8.1) > Ag-1.5%-MnO2/Eggshell (7.5) > Ag-5%-MnO2/Eggshell-R (7.2) > Ag-1.5%-MnO2/CaCO3-R (6.8) > MnO2-R (6) > Ag-0.5%-MnO2/Eggshell-R (3.2) > Ag/Eggshell-R (2.6). (Here, 'R' denotes hydrogen-based thermochemical reduction pretreatment.) The temperature required for 90% FA conversion (T90) at the same GHSV exhibited a contrary ordering: Ag/Eggshell-R (175 °C) > Ag-0.5%-MnO2/Eggshell-R (123 °C) > Ag-5%-MnO2/Eggshell-R (113 °C) > MnO2-R (99 °C) > Ag-1.5%-MnO2/Eggshell (96 °C) > Ag-3%-MnO2/Eggshell-R (93 °C) > Ag-1.5%-MnO2/Eggshell-R (77 °C). The eggshell catalyst outperformed the ones made of commercial calcium carbonate due to the presence of defects in the former. The MnO2 co-catalyst enhances the catalytic activities through the capture and activation of atmospheric oxygen (O2) with rapid catalytic regeneration. Also, MnO2 favorably captures the hydrogen of the adsorbed FA molecules to make the oxidation pathway thermodynamically more favorable.
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Affiliation(s)
- Kumar Vikrant
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea
| | - Ki-Hyun Kim
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea.
| | - Fan Dong
- Yangtze Delta Region Institute (Huzhou) & Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Huzhou 313001, China.
| | - Philippe M Heynderickx
- Center for Environmental and Energy Research (CEER), Engineering of Materials via Catalysis and Characterization, Ghent University Global Campus, 119-5 Songdo Munhwa-ro, Yeonsu-gu, Incheon 406-840, Republic of Korea; Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent B-9000, Belgium.
| | - Danil W Boukhvalov
- College of Science, Institute of Materials Physics and Chemistry, Nanjing Forestry University, Nanjing 210037, China; Institute of Physics and Technology, Ural Federal University, Mira Street 19, Yekaterinburg 620002, Russia
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Zhao L, Yang Y, Liu J, Ding J. Mechanistic insights into benzene oxidation over CuMn 2O 4 catalyst. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128640. [PMID: 35359105 DOI: 10.1016/j.jhazmat.2022.128640] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/28/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
The spinel-type CuMn2O4 catalyst exhibits good catalytic activity towards benzene oxidation, but the catalytic oxidation mechanism is not established. Theoretical calculations were implemented to unearth the reaction mechanism of benzene catalytic oxidation over CuMn2O4 catalyst through density functional theory (DFT). The results indicate that benzene adsorption on both Cu-terminated and Mn-terminated surfaces are controlled by the chemisorption mechanism. The Cu-terminated surface is more active for benzene adsorption than the Mn-terminated surface. Cu atom is regarded as the primary active site. During benzene catalytic oxidation, benzene firstly undergoes dehydrooxidation reaction to generate phenoxy group (C6H6* → C6H5* → C6H5O*). Two reaction channels are responsible for the ring-opening and oxidation reactions of phenoxy group, including benzoquinone- and cyclopentadienyl-dominated channels. In the benzoquinone-dominated channel, C6H4O2* is produced from phenoxy dehydrogenation and oxidation, and then decomposes into acetylene via the ring-opening reaction (C6H4O2* → C4H2O2* → C4H2O4* → C2H2*). Compared with the benzoquinone-dominated channel, the cyclopentadienyl-dominated channel is dominant for phenoxy group oxidation. Phenoxy group decomposes to generate cyclopentadienyl. C5H5* is dehydrogenated and oxidized to form cyclopentadienone. Finally, C5H4O* is oxidized to form carbon dioxide through a nine-step reaction pathway. The ring-opening reaction (C5H4O* → C3H2O*) has the highest energy barrier of 283.45 kJ/mol, and is identified as the rate-determining step of benzene catalytic oxidation.
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Affiliation(s)
- Liming Zhao
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yingju Yang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Jing Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Junyan Ding
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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He D, Ding X, Li S, Liang Y, Liu Y, Zhao M, Wang J, Chen Y. Constructing a Pt/YMn 2O 5 Interface to Form Multiple Active Centers to Improve the Hydrothermal Stability of NO Oxidation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20875-20887. [PMID: 35475604 DOI: 10.1021/acsami.2c01371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The hydrothermal stability of NO oxidation is the key to the practical application of diesel oxidation catalysts in diesel engines, which in the laboratory requires that NO activity does not decrease after aging for 10 h with 10% H2O/air at 800 °C. On the one hand, the construction of a metal/oxide interface can lead to abundant oxygen vacancies (Ov), which compensate for the loss of activity caused by the aggregation of Pt particles after aging. On the other hand, YMn2O5 (YMO) has excellent thermal stability and NO oxidation capacity. Therefore, a Pt/YMn2O5-La-Al2O3 (Pt/YMO-LA) catalyst was prepared by the impregnation method. The support of the catalyst, YMn2O5-La-Al2O3 (YMO-LA), was obtained by mixing high specific surface LA and YMO ball-milling. Under laboratory-simulated diesel exhaust flow, the NO oxidation performance of Pt/YMO-LA did not decrease after hydrothermal aging. Combining high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and oxygen temperature-programmed desorption (O2-TPD), the Pt/YMn2O5 interface was formed after hydrothermal aging, and the increased Ov can provide reactive oxygen to Pt and YMO. The cooperative catalysis of multiple active centers composed of Pt, YMO, and Ov is the crucial factor to maintain the NO oxidation performance. In addition, in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) show that an increase in Ov is beneficial to the adsorption and desorption of more nitrate and nitrite intermediates, thus achieving the hydrothermal stability of NO oxidation.
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Affiliation(s)
- Darong He
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
| | - Xinmei Ding
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
| | - Shanshan Li
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
| | - Yanli Liang
- College of Chemical Engineering, Sichuan University of Science & Engineering, Zigong 643002, Sichuan, China
| | - Yaxin Liu
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
| | - Ming Zhao
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
- Center of Engineering of Vehicular Exhaust Gases Abatement, Chengdu 610064, Sichuan, China
- Center of Engineering of Environmental Catalytic Material, Chengdu 610064, Sichuan, China
| | - Jianli Wang
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
- Center of Engineering of Vehicular Exhaust Gases Abatement, Chengdu 610064, Sichuan, China
- Center of Engineering of Environmental Catalytic Material, Chengdu 610064, Sichuan, China
| | - Yaoqiang Chen
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Wangjiang Road 29, Chengdu 610064, Sichuan, China
- Center of Engineering of Vehicular Exhaust Gases Abatement, Chengdu 610064, Sichuan, China
- Center of Engineering of Environmental Catalytic Material, Chengdu 610064, Sichuan, China
- Institute of New Energy and Low-Carbon Technology, Chengdu 610064, Sichuan, China
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10
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Effect of calcination temperature on the structure and performance of rod-like MnCeOx derived from MOFs catalysts. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112226] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Li Q, Chu X, Wang Y, Yang Q, Su Z, Peng Y, Si W, Li J. Metal–Support Interactions within a Dual-Site Pd/YMn 2O 5 Catalyst during CH 4 Combustion. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Qi Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xuefeng Chu
- Key Laboratory of Architectural Cold Climate Energy Management, Ministry of Education, Jilin Jianzhu University, Changchun 130118, China
| | - Ya Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Qilei Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Ziang Su
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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12
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Ding S, Zhu C, Hojo H, Einaga H. Enhanced catalytic performance of spinel-type Cu-Mn oxides for benzene oxidation under microwave irradiation. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127523. [PMID: 34736176 DOI: 10.1016/j.jhazmat.2021.127523] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Microwave-assisted heterogeneous catalytic oxidation of benzene was investigated over Cu-Mn spinel oxides. The spinel oxides were synthesized by a coprecipitation method from metal nitrate hydrolysis in a solution using tetramethylammonium hydroxide (TMAH) as a precipitation reagent. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption fine structure, scanning electron microscopy, transmission electron microscope and H2-temperature-programmed reduction studies. Microwave absorption by the Cu-Mn spinel oxide is mainly driven by dielectric losses (dielectric heating). Cu-Mn spinel oxide with a Cu/Mn ratio of 1 exhibited superior activity to single oxides under microwave heating, demonstrating lower apparent activation energy than that obtained under conventional heating. Microwave irradiation lowered the reaction temperature required for benzene oxidation compared with conventional heating. Transient tests were used to investigate the reactivity of oxygen species in the catalytic reaction, and the high reactivity of Cu-Mn spinel oxides was related to the high reactivity of lattice oxygen on the catalyst surface. The reactivity of the oxygen species was enhanced under microwave heating, leading to an enhanced benzene oxidation reaction. The combination of adsorption and catalytic oxidation processes using Cu-Mn spinel oxides and zeolites efficiently decomposed benzene at low concentrations.
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Affiliation(s)
- Siyu Ding
- Department of Molecular and Material Sciences, Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580, Japan
| | - Chen Zhu
- Department of Molecular and Material Sciences, Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580, Japan
| | - Hajime Hojo
- Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580, Japan
| | - Hisahiro Einaga
- Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580, Japan.
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13
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Yang Q, Li Q, Wang X, Wang X, Li L, Chu X, Wang D, Men J, Li X, Si W, Peng Y, Ma Y, Li J. Synergistic Effects of a CeO 2/SmMn 2O 5-H Diesel Oxidation Catalyst Induced by Acid-Selective Dissolution Drive the Catalytic Oxidation Reaction. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2860-2870. [PMID: 34995451 DOI: 10.1021/acsami.1c20965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A diesel oxidation catalyst (DOC) is installed upstream of an exhaust after-treatment line to remove CO and hydrocarbons and generate NO2. The catalyst should possess both good oxidation ability and thermal stability because it sits after the engine. We present a novel high-performance DOC with high steam resistance and thermal stability. A selective dissolution method is adopted to modify the surface physicochemical environment of CeO2-SmMn2O5. The X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, Raman, electron paramagnetic resonance, hydrogen temperature-programmed reduction, and temperature-programmed desorption results reveal that surface Sm cations are partially removed with the exposure of more Mn4+ and Ce3+ cations and the presence of active surface oxygen species. This mechanism benefits the oxygen transformation from Ce to Mn and promotes the Ce3+ + Mn4+ ↔ Ce4+ + Mn3+ redox cycle according to the in situ near-ambient pressure X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transformation spectroscopy results. Under laboratory-simulated diesel combustion conditions, the catalyst demonstrates excellent low-temperature oxidation catalytic activity (CO and C3H6 conversion: T100 = 250 °C) compared to a Pt-based catalyst (CO and C3H6 conversion: T100 = 310 °C) with a WHSV of 120,000 mL g-1 h-1. Specifically, NO conversion reaches 68% when the temperature is approximately 300 °C.
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Affiliation(s)
- Qilei Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Qi Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Xiyang Wang
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Xiao Wang
- Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C5, Canada
| | - Lei Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Xuefeng Chu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Dong Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Jishuai Men
- Air Pollution Control Laboratory, Shandong Daming Scinece and Technology Co., Ltd., Tengzhou, Shandong 277500, P. R. China
| | - Xinbo Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Yongliang Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
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14
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Direct electron transfer process-based peroxymonosulfate activation via surface labile oxygen over mullite oxide YMn2O5 for effective removal of bisphenol A. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.119924] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Yang Q, Wang X, Wang X, Li Q, Li L, Yang W, Chu X, Liu H, Men J, Peng Y, Ma Y, Li J. Surface Reconstruction of a Mullite-Type Catalyst via Selective Dissolution for NO Oxidation. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03955] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Qilei Yang
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Xiao Wang
- Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C5, Canada
| | - Xiyang Wang
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Qi Li
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Lei Li
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Weinan Yang
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Xuefeng Chu
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Hao Liu
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Jishuai Men
- Air Pollution Control Laboratory, Shandong Daming Science and Technology Co., Ltd., Shandong 277500, P. R. China
| | - Yue Peng
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Yongliang Ma
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Junhua Li
- School of Environment, Tsinghua University, Beijing 100084, P. R. China
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16
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Chen Y, Cai Z, Wang D, Yan Y, Wang P, Wang X. Air-Stable Mn doped CuCl/CuO Hybrid Triquetrous Nanoarrays as Bifunctional Electrocatalysts for Overall Water Splitting. Chem Asian J 2021; 16:3107-3113. [PMID: 34467668 DOI: 10.1002/asia.202100616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/22/2021] [Indexed: 11/07/2022]
Abstract
The development of highly efficient non-precious metal catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is key for large-scale hydrogen evolution through water splitting technology. Here, we report an air-stable Cu-based nanostructure consisting of Mn doped CuCl and CuO (CuCl/CuO(Mn)-NF) as a dual functional electrocatalyst for water splitting. CuCl is identified as the main active component, together with Mn doping and the synergistic effect between CuCl and CuO are found to make responsibility for the excellent OER and HER catalytic activity and stability. The assembled electrolyzes also exhibit decent water splitting performance. This work not only provides a simple method for preparing Cu-based composite catalyst, but also demonstrates the great potential of Cu-based non-noble metal electrocatalysts for water splitting and other renewable energy conversion technologies.
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Affiliation(s)
- Ying Chen
- CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), Shanghai, 200050, P. R China.,School of Materials Science & Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, P. R. China
| | - Zhengyang Cai
- CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), Shanghai, 200050, P. R China.,School of Materials Science & Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, P. R. China
| | - Ding Wang
- School of Materials Science & Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, P. R. China
| | - Ya Yan
- CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), Shanghai, 200050, P. R China
| | - Ping Wang
- CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), Shanghai, 200050, P. R China
| | - Xianying Wang
- CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), Shanghai, 200050, P. R China
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17
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Xu Z, Yang W, Si W, Chen J, Peng Y, Li J. A novel γ-like MnO 2 catalyst for ozone decomposition in high humidity conditions. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126641. [PMID: 34329114 DOI: 10.1016/j.jhazmat.2021.126641] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/29/2021] [Accepted: 07/11/2021] [Indexed: 06/13/2023]
Abstract
MnO2 catalysts have been widely studied for catalytic gaseous ozone decomposition. However, their poor moisture resistance often leads to undesirable catalytic effects in the presence of high humidity. In this study, a novel catalyst with γ-like MnO2 was synthesized using the selective dissolution method on LaMnO3 perovskites. The as-prepared catalyst exhibited quite stable ozone conversion of ~90% within 12 h under 75% relative humidity (400-800 ppm of ozone, 30 °C, 150 000 mL·g-1·h-1 of WHSV). In contrast, traditional γ-MnO2 catalyst showed deficient resistance to H2O and sensitivity to space velocity. Detailed characterizations showed that the larger number of oxygen vacancies induced by structure reconstruction of the γ-like MnO2 and residual La3+ cations facilitated ozone decomposition in humid atmosphere. Finally, the reaction rate of ozone decomposition was proposed by a kinetic study, which further proved that the amount and hydrophilicity of oxygen vacancies are the determinants of the first-order reaction rate constant.
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Affiliation(s)
- Zhenghao Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Wenhao Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China.
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, PR China
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18
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A Hierarchical Architecture of Functionalized Polyaniline/Manganese Dioxide Composite with Stable-Enhanced Electrochemical Performance. JOURNAL OF COMPOSITES SCIENCE 2021. [DOI: 10.3390/jcs5050129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
As one of the most outstanding high-efficiency and environmentally friendly energy storage devices, the supercapacitor has received extensive attention across the world. As a member of transition metal oxides widely used in electrode materials, manganese dioxide (MnO2) has a huge development potential due to its excellent theoretical capacitance value and large electrochemical window. In this paper, MnO2 was prepared at different temperatures by a liquid phase precipitation method, and polyaniline/manganese dioxide (PANI/MnO2) composite materials were further prepared in a MnO2 suspension. MnO2 and PANI/MnO2 synthesized at a temperature of 40 °C exhibit the best electrochemical performance. The specific capacitance of the sample MnO2-40 is 254.9 F/g at a scanning speed of 5 mV/s and the specific capacitance is 241.6 F/g at a current density of 1 A/g. The specific capacitance value of the sample PANI/MnO2-40 is 323.7 F/g at a scanning speed of 5 mV/s, and the specific capacitance is 291.7 F/g at a current density of 1 A/g, and both of them are higher than the specific capacitance value of MnO2. This is because the δ-MnO2 synthesized at 40 °C has a layered structure, which has a large specific surface area and can accommodate enough electrolyte ions to participate the electrochemical reaction, thus providing sufficient specific capacitance.
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19
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Yang W, Wang Y, Yang W, Liu H, Li Z, Peng Y, Li J. Surface In Situ Doping Modification over Mn 2O 3 for Toluene and Propene Catalytic Oxidation: The Effect of Isolated Cu δ+ Insertion into the Mezzanine of Surface MnO 2 Cladding. ACS APPLIED MATERIALS & INTERFACES 2021; 13:2753-2764. [PMID: 33401915 DOI: 10.1021/acsami.0c19972] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Heterocation insertion and substitution in tunnels and mezzanines of MnO2 present significant influences on the microchemical environment at the surfaces and interfaces. An innovative surface in situ doping modification method via Cu2+-H+/KMnO4 treatment was applied onto the Mn2O3 surface to provide Mn2O3@MnO2 nanospheres. Cu was stabilized into resulting MnO2 cladding substituting original K+ during a mild comproportionation reaction between Mn(VII) and Mn(III). The Cu25 (Cu(II): Mn(VII)atomic = 25%) catalyst shows significant promotion of the catalytic performance compared with bare Mn2O3 and Cu0 (without Cu involving). Isolated Cuδ+ was predominantly inserted into the mezzanine of the [MnO6]δ- layers in MnO2 instead of K+, leading to slight electron transfer from Cuδ+ to outermost Mn(4-ε)+ and a decrease of interlayer spacing as well as crystallinity. Such a configuration facilitates the formation of additional oxygen vacancies, promoting the redox ability and oxygen mobility at relatively low temperatures. The mechanistic study reveals that Cuδ+ in MnO2 cladding boosts the activation of toluene (methyl) to form benzoates and propene (methyl and double bonds) to form carboxylates, enhancing the chemical adsorption of reactants. Moreover, it also inhibits the unfavored accumulation of incomplete oxidized intermediates on the surface at high temperatures.
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Affiliation(s)
- Wenhao Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Ya Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Weinan Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Hao Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhenguo Li
- National Engineering Laboratory for Mobile Source Emission Control Technology, China Automotive Technology & Research Center Co., Ltd, Tianjin 300300, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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