MICROPOROUS AND MESOPOROUS MATERIALS
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2021
·
IF 5.455
Yanliang Zhai,Yunshan Shang,Luoming Zhang,Xiaoling Meng,Yanjun Gong,Lirong Zheng,Jing Zhang,Ping Liu
Hydrothermally modified nanosheet ZSM-5 zeolite by directly using MnO x nanoparticles was carried out and this substantially offered a high performance catalyst for methanol to propylene (MTP) reaction. The properties of as synthesized ZSM-5 nanosheets with different MnO x amounts (NS-x) were compared with ZSM-5 nanosheets modified by impregnation method (IM-0.5) and physically mixed method (PM-0.5), respectively. The initial state of MnO x nanoparticles was close to Mn 2 O 3 with 20 nm in size. XRD , H 2 -TPR and XAFS results confirmed under high temperature hydrothermal condition, the Mn 2 O 3 nanoparticles disaggregated into Mn 2 O 3 clusters and entered the framework defects of nanosheet zeolite with high dispersion. Infrared spectra of hydroxyl groups (OH-IR) showed that the Mn 2 O 3 clusters were bonded with silanol defects both on the surface and inside zeolite, which substantially increased the stability of Mn 2 O 3 clusters and healed the framework defects. In contrast, the Mn species in the impregnated sample was close to the co-existence of Mn 2+ ions and MnO 2 nanoparticles with 2–3 nm, no interaction between Mn species and Si–OH group was determined. Notably, the typical sample (NS-0.5) with MnO x cluster modification performed much higher propylene selectivity and catalytic stability (~52%, 240 h, WHSV = 3 h −1 ), while the conventional IM-0.5 and PM-0.5 showed poor propylene selectivity (48%, 46%) and catalytic stability (166 h, 133 h) in MTP reaction. The excellent result should be attributed to the subtle control of external strong acid and the less structural defects, due to specific existence of bonded Mn 2 O 3 clusters.
研究领域:
化学
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材料科学
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催化
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Hengxi He,Weirui Chen,Jiaxin Zhou,Xukai Li,Jing Wang,Laisheng Li
The sluggish Me (n+m)+ / Me n+ redox cycle greatly restrained the catalytic ozonation performance of metal-based catalysts. To break this bottleneck, we adopted an interfacial oxidation reaction to create electron-deficient/rich centers within carbon skeleton derived from MOF (C-MOF) by utilizing the electronegativity difference between cerium (Ce) and manganese (Mn), and evaluated its catalytic ozonation activity with ibuprofen (IBP) as model pollutant. XPS, H 2 -TPR, LSV and EPR characterizations as well as DFT calculation demonstrated that there existed electron-deficient Ce sites and electron-rich Mn sites on CeO x /MnO x /C-MOF. Under the co-function of Ce and Mn sites, CeO x /MnO x /C-MOF/O 3 process achieved 100% IBP removal in 90 min, which was 3.1 times of sole ozonation process. IBP could be absorbed at the electron-deficient Ce center and directionally donate its electron to the O 3 around electron-rich Mn center. Singlet oxygen ( 1 O 2 ) played the major role in IBP degradation. Cl − , HCO 3 − , NO 3 − and SO 4 2− demonstrated limited inhibitions on IBP degradation. This work provided a sustainable strategy for breaking the rate-limiting step in the traditional catalytic ozonation.
研究领域:
环境科学
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催化
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
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IF 3.375
Xiangzhan Meng,Yongqiang Zhang,Zengxi Li,Hui Wang,Suojiang Zhang
Au supported on monoclinic ZrO2 (Au/m-ZrO2) prepared by deposition–precipitation method showed excellent catalytic performance in the aerobic oxidation of amino alcohols to amino acids, i.e., glycine, alanine, serine, β-alanine, and 2-aminobutyric acid. The Au particle size and valence distribution of the gold species were adjusted by calcination temperature, as demonstrated by XRD, TEM, UV–vis DRS, XPS, and H2-TPR, which significantly influenced the catalytic activity but not the selectivity of amino acids. Metallic gold atoms on the surface were shown to be the active sites by the correlation between reaction rate per mole of metallic Au and Au particle size. The kinetics of oxidation of monoethanolamine (MEA) was studied in detail, and the results indicated that MEA oxidation is a first-order reaction with an activation energy of 52.8 kJ·mol–1.
研究领域:
催化
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化学工程
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材料科学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Zhengfeng Gu,Daiwei Liu,Mengnan Yu,Teng Bao,Xiaowei Liu,Ling Zhang,Haitao Ding,Zhimin Yu,Chengxun Deng
The synthesis of supported transition metal oxides with satisfactory low-temperature catalytic performance and application potential is still a challenge for the complete degradation of VOCs. Ni-Cu-loaded TiO 2 catalysts were prepared by an impregnation method. The lattice defect and oxygen vacancy concentrations of the prepared materials could be tuned by controlling the Ni/Cu molar ratio and the mass proportion of the TiO 2 support. 5Ni-Cu/TiO 2 exhibited the best catalytic activity and showed superior catalytic stability during complete toluene oxidation . The obtained catalysts were fully characterized by XRD, FT-IR, TEM, N 2 adsorption analysis, XPS, H 2 -TPR, O 2 -TPD, TPD analysis, and XPS. The 5Ni-Cu/TiO 2 catalyst had improved pore sizes and specific surface area, had more oxygen vacancies on its surface, had increased concentrations of adsorbed and lattice oxygen species, and had good redox properties; these characteristics were favorable for low-temperature catalytic performance and catalytic stability. Cyclic transformations of metal valence states between Cu + and Cu and between Ni and Ni 2+ were observed in the catalytic system. A potential catalytic reaction process based on the M-vK mechanism was proposed. This work serves as a reference for the application of supported transition metal catalysts for the degradation of VOCs.
研究领域:
催化
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 86
·82707-82715
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IF 3.289
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
A series of Mn/CeSiOx catalysts were prepared by the wet impregnation method and used for selective catalytic reduction of NO with NH3. As can be seen from the experimental results, the Mn/CeSiOx catalyst with a Ce/Si molar ratio of 2/1 showed excellent low-temperature SCR activity, high N2 selectivity and excellent SO2 and H2O tolerance. The relationship between the CeSiOx support and the SCR performance of Mn/CeSiOx (2 : 1) catalyst was investigated based on the characterization results of N2 adsorption, XRD, XPS, H2-TPR, NH3-TPD and in situ DRIFT. The strong interaction between Ce and Si resulted in the good dispersion of Mn species on the support; correspondingly, the redox ability and NH3 adsorption capacity were greatly enhanced. The results of in situ DRIFT study revealed that the NH3-SCR reactions over Mn/CeO2 and Mn/CeSiOx (2 : 1) mainly obeyed both the E–R mechanism and the L–H mechanism. Furthermore, the formation of more Mn4+ and chemisorbed oxygen greatly facilitates the oxidation of NO to NO2, as a result, promoting the low-temperature SCR performance of Mn/CeSiOx (2 : 1).
研究领域:
催化
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环境科学
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化工
✓ 已验证
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 4
·2040-2046
·
IF 3.361
Yang Liu,Xin Liang,Jie Zhang,Jimmy Yun,Zuobo Yang
In this study, monodispersed NiRu nanocrystals with a diameter of 3 nm were synthesized at 90 °C via a tuning hot-inject method to lower the temperature of the organic phase synthesis of monodispersed nanomaterials. The key factor for the nanocrystalline formation of NiRu alloy nanocrystals was summarized in detail. Simultaneously, the synergistic effect of Ni and Ru in CO2 methanation was explored. Doping trace Ru can significantly improve the conversion rate of CO2 methanation and CH4 selectivity. The underlying mechanism was studied in detail via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed hydrogen reduction (H2-TPR) and desorption (H2-TPD) tests, and temperature-programmed desorption of CO2 (CO2-TPD). This study gives out a new way for the general synthesis of monodisperse nickel-based nanocrystals and provides a reference for the development and application of monodispersed nanoparticles for CO2 methanation.
研究领域:
材料科学
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催化
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纳米技术
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
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2022
·
IF 4.654
Beibei Feng,Chunlan Qin,Ying Shi,Lidong Zhang
Ethanol is extensively used in the transport field as a clean additive and alternative for gasoline in internal combustion engines, although its incomplete combustion inevitably releases harmful species to humans and the environment. Mn-based oxides, one of the most promising materials for catalytic combustion, have attracted considerable interest due to their excellent catalytic performance and low cost. In this work, hydrothermal methods were used to synthesize the different manganese oxides with distinct morphologies (1D-Mn3O4 nanorod, 2D-Mn3O4 nanoplate, and 3D-Mn3O4 nano-octahedron). Meanwhile, catalytic activity over these three catalysts was evaluated for ethanol combustion. The physicochemical properties of these samples were characterized by X-ray diffraction, N2-BET, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Raman, and H2-TPR. Among the three catalysts, the Mn3O4 nanoplate exhibited an optimal performance at a space velocity of 60 000 mL g–1 h–1. The apparent activation energy associated with the nanoplate material (25.6 kJ/mol) was lower than that of the 1D-Mn3O4 nanorod (28.9 kJ/mol) and 3D-Mn3O4 nano-octahedron (37.3 kJ/mol). According to characterization results, the Mn3O4 nanoplate catalyst exhibits a small crystal size, large surface area, more exposed (112) facets, abundant Mn4+, and defective structure, contributing to a superior catalytic performance at the high space velocity of 120 000 mL g–1 h–1. In addition, we conclude that the catalytic combustion of ethanol follows the Mars-van Krevelen mechanism based on the kinetic simulation results of experimental data.
研究领域:
化学工程
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催化
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材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）