JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Fuping Song,Juping Zhang,Dongfang Li,Tao Zhu,Xing Zhu,Hua Wang
Oxidative dehydrogenation (ODH) of ethylbenzene is a promising process for styrene production. However, its application is limited by product overoxidation and purification requirements due to the co-feeding of mild oxidants. Herein, we report a facile manganese-based catalyst (K/Mn 3 O 4 -Al 2 O 3 ) and achieve competitive styrene selectivity of 88 % and ethylbenzene conversion of 95 % at 450 ℃ (84 % yield vs. ∼ 60 % yield in commercial dehydrogenation process at 600 ℃) under a cyclic redox ODH scheme. The introduction of Al 2 O 3 into MnO x restructures composite oxides and depresses bulk lattice-oxygen migration for the partial oxidation of ethylbenzene. The surface modification using potassium creates reactive sites and regulates surface properties, achieving ethylbenzene activation and high conversions. Highly active lattice oxygen in catalysts after bulk and surface modifications selectively converts ethylbenzene to styrene and water. This study provides an understanding of roles of manganese-based catalysts in styrene generation and offers a strategy to modulate lattice oxygen on catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 10
·1267
·
IF 4.501
Ju Gao,Xu Dong,Zhenguo Li,Yuankai Shao,Xiaoning Ren,Kaixiang Li,Yiren Lu
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, GdMn2O5mullite (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−1h−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.
研究领域:
环境科学
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催化化学
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材料科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 12
·885
·
IF 3.8
Yulin Sun,Yiwei Zhang,Baoqing Hou,Yong He,Wubin Weng,Yanqun Zhu,Zhihua Wang
Formaldehyde (HCHO) is known as one of the important indoor organic pollutants. How to remove and decompose the low concentration of formaldehyde at room temperature is important for indoor environments. Catalytic ozonation is an efficient method to thoroughly remove HCHO at room temperature, with high efficiency and few byproducts. A series of MnOx/γ-Al2O3catalysts were prepared in this work via the impregnation method and treated with different reagents (acid, alkali, and H2O2) to evaluate their catalytic activity for HCHO removal. The results showed that MnAl-II (acid treatment) performed well in activity tests, reaching a nearly 100% HCHO conversion at an O3/HCHO of 2.0 and attaining a CO2selectivity of above 95% at an O3/HCHO of 3.0 at 30 °C, with almost no ozone residual existing. The larger specific surface area, abundant oxygen vacancies, and higher number of acid sites contributed to the excellent performance of MnAl-II. Stability and H2O resistance tests of MnAl-II were also conducted. To reveal the intermediate product formation and further investigate the reaction mechanism of HCHO ozonation, in-situ DRIFTS measurement was carried out combined with DFT calculations.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Jian Liu,Rui-tang Guo,Ming-yuan Li,Peng Sun,Shu-ming Liu,Wei-guo Pan,Shuai-wei Liu,Xiao Sun
Mn/TiO 2 catalyst is a promising candidate for future utilization in low-temperature NH 3 -SCR reaction, but its bad resistance to SO 2 is still a great challenge for practical application. In this study, Eu was successfully used as the additive to improve its resistance to SO 2 under SCR conditions, while the pretreatment of Mn/TiO 2 and MnEu/TiO 2 catalyst by SO 2 + O 2 had a strong deactivation effect on them. In situ DRIFT study clarified that the deactivation of Mn/TiO 2 -S (SCR + SO 2 ), Mn/TiO 2 -S (SO 2 + O 2 ) and MnEu/TiO 2 -S (SO 2 +O 2 ) were mainly originated from the inhibited adsorption of NH 3 and NOx species, as well as the formation of a large amount surface sulfate species on them, which had a strong blacking effect on the SCR reactions over the three catalysts via both E-R and L-H routes. After the addition of Eu, SCR reaction over MnEu/TiO 2 catalyst with the existence of SO 2 took place through L-H pathway, accompanied by the generation of less surface sulfate species, which brought about the excellent SO 2 tolerance of MnEu/TiO 2 catalyst under SCR conditions.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Fawang Wu,Bomin Feng,Wei Li,Heng Liu,Yihong Mei,Weihua Hu
Transition metal on nitrogen-doped carbons (M-N-C, M = Fe, Co, Mn, etc.) are a group of promising sustainable electrocatalysts toward oxygen reduction reaction (ORR). Compared to its Fe, Co analogues, Mn–N–C possesses the advantage of being inert for catalyzing Fenton reaction, and thus is expected to offer higher durability, but its ORR activity needs essential improvement. Herein, an efficient Mn–N–C ORR catalyst composed of Mn 3 O 4 nanoparticles supported on nitrogen-doped carbon was successfully synthesized by pyrolysis of cyanamide/Mn-incorporated polydopamine (PDA) film coated carbon black (CB), where the presence of N-rich cyanamide confers abundant Mn-N x active sites and rich micropore/mesopores to the catalyst. In an alkaline medium , as-synthesized Mn–N–C electrocatalyst outperforms commercial Pt/C catalyst in terms of onset potential (0.98 V, vs. RHE), half-wave potential (0.868 V, vs. RHE), and limiting current density . Meanwhile, it exhibits excellent durability and resistance to methanol. In a Zinc-air primary battery , it demonstrates better performance as a cathodic catalyst than Pt/C.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Mingxun Han,Fanji Liu,Xiangxiang Li,Xiqing Zhang,Yiren Lu,Yanjun Lin,Lihong Zhang
A series of manganese-based catalysts supported on γ-Al 2 O 3 with low loading amount of manganese from 0.5% to 2.0% were prepared by incipient impregnating method. All catalysts were tested on non-oxidative dehydrogenation of isobutane at 600 °C. In order to explore physicochemical properties of all catalysts, various characterizations including XRD, H 2 -TPR, XPS, UV-vis, NH 3 -TPD and TG were carried out on manganese-based catalysts. The experimental results indicated that MnO x species were highly dispersed on γ-Al 2 O 3 support, and both Mn 2+ and Mn 3+ ions are main active species for isobutane dehydrogenation. The reduced catalyst 1.5%Mn/ γ -Al 2 O 3 exhibited the most optimal dehydrogenation performance among all catalysts, reaching at isobutane conversion of 36% and isobutene selectivity of 79%. The main reasons for the excellent activity and selectivity of 1.5%Mn/ γ -Al 2 O 3 were related to the high proportion of low valence manganese ions including Mn 2+ and Mn 3+ as well as the high concentration of medium strong acid sites and weak strong acid strength.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2025
·
IF 3.9
Yingshan Xue,Ping Wang,Cheng Yang,Jiasai Yao,Tianbao Zhang,Xin Zhang,Jing Xiong,Xiaohua Sun,Yuechang Wei,Zhenxing Li
Nitrogen oxides are an industrial and domestic waste gas, which pollutes the air and affects health. In this paper, we use the template method to achieve the doping of alkaline earth metals, and the alkaline earth metals are doped into cerium-manganese-based three-dimensional ordered macroporous (3DOM) catalysts to detect NO oxidation. The introduction of alkaline earth metals can improve the stability and thickness of macroporous results, which increases the contact area between the catalyst and reactant gases. At the same time, alkaline earth metal doping can promote the formation of more oxygen vacancies and unsaturated structures, and improve the catalytic activity of NO oxidation. The NO conversion rate of CM-3Mg doped with 3% Mg was 61.25% at 250°C, and the NO conversion rate was the highest at 303°C, which was 79.2%. This study provides a promising catalyst candidate for NO oxidation in practical applications.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 37
·24947-24954
·
IF 10.7
Xuebin Wang,Miao He,Ping Wang,Jiasai Yao,Jing Xiong,Xin Zhang,Xiaohua Sun,Yuechang Wei,Zhenxing Li
Alkali metals can control the redox potential of a reaction system as well as modify the surface electronic structure and improve the stability of a catalyst. Herein, we doped an alkali metal into a cerium manganese-based three-dimensional ordered macroporous (3DOM) catalyst for NO oxidation and soot combustion; the doping was achieved using a self-sacrificing polymethyl methacrylate template and an excess impregnation method. The introduction of alkali metals can provide a rough pore surface, which increases the contact area between the catalyst and the reactant gas. Meanwhile, alkali metal doping can promote the formation of more oxygen vacancies and unsaturated structures and increase the catalytic activity for NO oxidation and soot combustion. 5% K-doped CM-5K achieved an NO conversion rate of 81.9% at 250 °C and of nearly 100% at 320 °C. CM-5K also demonstrated remarkable stability in cycling stability tests for NO oxidation and soot combustion. This work provides a promising catalyst candidate for NO oxidation and soot combustion in practical application.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Qianlin Huang,Puzhen Zhao,Weiwei Wang,Lu Lv,Weiming Zhang,Bingcai Pan
Cost-efficient and durable manganese-based catalysts are in great demand for the catalytic elimination of volatile organic compounds (VOCs), which are dominated not only by the nanostructures but also by the oxygen vacancies and Mn–O bond in the catalysts. Herein, a series of nanostructured Co–Fe-doped-δ-MnO2 catalysts (Co–Fe-δ-MnO2) with high dispersion were in situ fabricated by employing metal–organic-frameworks (MOFs) as reducing agents, dopants, and templates all at the same time. The as-obtained Co–Fe-δ-MnO2-20% catalyst exhibited robust durability and high catalytic activity (225 °C) for toluene combustion even in the presence of 5 vol % water vapor, which is 50 °C lower than that of pristine δ-MnO2. Various characterizations revealed that the homogeneously dispersed codoping of Co and Fe ions into δ-MnO2 promotes the generation of oxygen vacancies and weakens the strength of the Mn–O bond, thus increasing the amount of adsorbed oxygen (Oads) and improving the mobility of lattice oxygen (Olatt). Meanwhile, due to successfully inheriting the framework structures of MOFs, the obtained catalyst exhibited a high surface area and three-dimensional mesoporous structure, which contributes to diffusion and increases the number of active sites. Moreover, in situ DRIFTS results confirmed that the toluene degradation mechanism on the Co–Fe-δ-MnO2-20% follows the MVK mechanism and revealed that more Oads and high-mobility Olatt induced by this novel method contribute to accumulating and mineralizing key intermediates (benzoate) and thus promote toluene oxidation. In conclusion, this work stimulates the opportunities to develop Co–Fe-δ-MnO2 as a class of nonprecious-metal-based catalysts for controlling VOC emissions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2020
·
IF 3.104
Youchun Pan,Qijie Jin,Bingxu Lu,Yan Ding,Xin Xu,Yuesong Shen,Yanwei Zeng
MnCeO x /TiO 2 has been widely used in selective catalytic reduction (SCR) of NO x at low temperature. However, it is often poisoned in the presence of water vapor and sulfur dioxide . In this work, the promotion mechanism of Ba modification was investigated. Results show that the doped BaO reacts with CeO 2 and forms BaCeO 3 . This unique perovskite structure of BaCeO 3 significantly enhances NO oxidation and NH 3 activation of MnCeO x /TiO 2 catalyst so that the NO conversion and the resistances to SO 2 improve. It is found that Ba species obviously promotes the NO adsorption ability and improve the redox properties of MnCeO x /TiO 2 catalyst. While the acid properties of the catalyst are inhibited by Ba modification and among which Lewis acid sites are dominant for both MnCeO x /TiO 2 and MnCe(Ba)O x /TiO 2 catalysts. Furthermore, in situ DRIFT experiments reveal that the NO reduction upon MnCeO x /TiO 2 and MnCe(Ba)O x /TiO 2 catalysts follows both E-R and L-H mechanisms, in which L-H is preferred. Ba species enhances the formation of active nitrate species, which accelerates the NO reduction through L-H mechanism. It is interesting that although Ba species weakens the NH 3 adsorption, it induces the ammonia conversion to coordination ammonia, which in turn accelerates the catalytic reaction .
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Liangyong Chen,Rui Mao
Developing robust catalytic oxygen carriers (COC) to make Chemical-looping Oxidation Coupling of Methane (CL-OCM) economical and practical remains a big challenge. This work modified the Mn-based catalysts for co-feed OCM and tried to adapt them into CL-OCM process. COCs were specially designed with high faction of Mn-oxides to improve oxygen storage, with supports (pelletized from SiO 2 , MgO and TiO 2 ) of stable and porous structure to improve cyclic stability and to tune lattice oxygen reactivity, and with Na + dopant to improve conversion and selectivity. Among the COCs, Mn20Na2Si and Mn20Si (20 wt% Mn 2 O 3 supported on SiO 2 with/without 2.0 wt% Na 2 CO 3 dopants) exhibited excellent methane coupling activity. The averaged CH 4 conversion, C 2 selectivity and yield of Mn20Na2Si upon multiple redox cycles were 21.4 %, 79.6 % and 17.03 %, respectively. It showed improvements in C 2 selectivity and yield by 187 % and 163 % compared to Mn20Si. This work tried to establish the relationships between CL-OCM performance and lattice oxygen behaviors, since COC transports lattice oxygen to promote methane coupling as it performs as a catalyst during CL-OCM reduction. It is found that high C 2 -selectivity and CH 4 conversion are benefited from the constant oxygen transporting rate. Na + dopant improved the concentration of surface lattice oxygens, tuned the spatial arrangement of metal oxides, and stabilized the surface lattice oxygen in cyclic reactions. Due to Na + -doping, carbon deposition on Mn20Na2Si was avoided, and catalyst deactivation as well. Finally, a mechanism was developed to reveal how lattice oxygen species and their releasing rates affected surface reaction network, CH 4 conversion, C 2 selectivity and cyclic stability.
研究领域:
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2022
·
IF 11.357
Tingting Pan,Hua Deng,Yuqin Lu,Jinzhu Ma,Lian Wang,Changbin Zhang,Hong He
The miscellaneous volatile organic compounds (VOCs) in industrial flue gas streams usually demonstrate significant mutual inhibition effects, and the behavior of a particular VOC in mixtures is not clear, which hinders the application of catalytic technology. This study examines the catalytic oxidation and mixing effects of representative VOCs in industrial exhausts, consisting of acetone (AC), ethyl acetate (EA), and toluene (Tol), on common Mn-based catalysts (e.g., MnO2, Mn2O3, LaMnO3, and Mn3O4) by means of intrinsic activity evaluation, coadsorption, VOC temperature-programmed oxidation, in situ diffuse reflectance infrared Fourier transform spectroscopy, and gas chromatography–mass spectrometry. The results showed no inhibiting effect on the conversion of these VOCs when combusted together; instead, a significant mutual promotion effect was found, especially on Tol destruction, with a sharp decrease in the Tol T50 from 214 to 158 °C on MnO2. It is proposed for the first time that the addition of AC/EA in Tol combustion leads to the generation of o/m-methyl phenol, which changes the rate-determining step of the ring-opening process, thus elevating the conversion of Tol together with AC and EA in the mixture at low temperatures.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）