CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Jiancheng Wang,Zhaoliang Peng,Ying Chen,Weiren Bao,Liping Chang,Gang Feng
Cu-SSZ-13/cordierite monolithic catalyst was prepared by in situ hydrothermal synthesis method. The physicochemical properties of the as-prepared Cu-SSZ-13/cordierite were investigated by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, N 2 -adsorption, inductively coupled plasma, X-ray photoelectron spectroscopy, and solid-state NMR techniques. The removal of nitrogen oxides (NO x ) from simulated diesel vehicle exhaust gas was performed using fixed-bed reactor. The effects of crystallization time and addition of HF during hydrothermal synthesis, reaction space velocity, and aging treatment of catalyst on the catalytic performances of NO x reduction reactions were investigated. The results indicate that the optimum crystallization time was 72 h. Highly crystalline structure of zeolite Cu-SSZ-13 was formed, in a close combination with a carrier, via one step hydrothermal process. Cu-SSZ-13/cordierite showed excellent DeNO x performance for selective catalytic reduction (SCR) and anti-aging properties in a simulated diesel exhaust gas under a high space velocity. At a high space velocity of 72,000 h −1 , the highest conversion and N 2 selectivity of 94% and 90%, respectively, were achieved. After the aging for 50 h at 720 °C, NO x reduction rate was still >80% in the temperature range of 350–550 °C. The larger height to diameter ratio of the same catalysts enhanced the NH 3 -SCR catalytic activity and broadened the active temperature window. The addition of HF increased the catalytic activity and anti-aging performance of the sample.
研究领域:
催化材料
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Hao Li,Cuiwei Li,Linghao Wu
Porous cordierite ceramics with a single phase, high porosity and high strength were in-situ prepared using periclase, alumina and silica powders as raw materials by foam-gelcasting technique firstly. The reaction mechanism of preparing process was investigated via TG-DTA, X-ray diffraction, scanning electron microscope and electron energy disperse spectroscopy. The results confirmed that Mg(OH) 2 was formed during the preparation of green body and cordierite was formed at 1325 °C through the intermediate phases of cristobalite and MgAl 2 O 4 spinel. Samples with different performance have been fabricated by changing experimental parameters. Through altering holding time, sintering temperature and solid content in a certain scale, high porosity (83.9–89.2%), low bulk density (0.28–0.42 g/cm 3 ) and high compressive strength (0.9–4.7 MPa) were obtained. The SEM images showed that the pore structure of the as-prepared material was multiscale, the cordierite grains were irregular and the grain size was below 5 μm. The method used in this paper shows great promise for preparing porous cordierite ceramics with single phase, high porosity and high strength.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2022
·
IF 9.93
Wei Chen,Alicia C. Garofalo,Haining Geng,Yan Liu,Dongwen Wang,Qiu Li
Cesium-based geopolymer is more refractory than K + and Na + based geopolymers after the transformation to ceramic material, whose thermal resistance feature is highly appreciated by some industries, especially in the engineering field where the materials in some cases are exposed to environments with high temperatures. In this study, cesium-activated geopolymer composites (CsGPc), with 5–35 wt% cordierite reinforcements, were prepared and evaluated on the high temperature performance. When 35 wt% cordierite was added, the compressive strength increased by 72% compared to the reference plain CsGP. Residual compressive strength (after heating at 1400 °C) of CsGPc with 35 wt% cordierite increased by 106% compared to the specimen before the thermal exposure . After thermal exposure up to 1400 °C, the geopolymer matrix was transformed into a pollucite-based ceramic composite. Amorphous phases in CsGPc gradually crystallized to form pollucite as the main phase with cordierite as secondary phase. The microstructure of CsGPc and the obtained ceramics showed a clear sintering process and crystallization of pollucite. Shrinkage was reduced and the coefficient of thermal expansion (CTE) varied from 4.50 to 1.89 × 10 −6 K −1 with the cordierite inclusion. The performance of obtained ceramic composites was superior compared to the initial CsGPc, which would be excellent for heat resistance applications.
研究领域:
材料科学
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无机化学
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产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2023
·Vol. 21
·期 2
·829-843
·
IF 2.1
Yang Yang,Jiaqi Yan,Shujia Cheng,Gang Liu,Bensong Chen,Kang Zheng,Lin Chen,Xingyou Tian
Cordierite ceramic is usually used for diesel particulate filter owing to its excellent low thermal expansion coefficient and high thermal shock resistance properties. However, the co-exited intermediate spinel phase can deteriorate the thermal and mechanical performances of cordierite ceramic product, because the spinel phase has much higher thermal expansion coefficient comparing to that of cordierite. In this study, two methods are utilized to reduce the spinel impurity in the cordierite ceramic. On the one hand, rational reaction resources were introduced to decrease spinel production. The formation of intermediate spinel phase is systematically researched by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman characterizations and the results clarified the preference of path “Enstatite + Mullite → Cordierite” for less spinel production in comparison to path “Enstatite + Al 2 O 3 → Cordierite + Spinel.” Additionally, MgO was introduced as fluxing agent to promote liquid-phase sintering, thus facilitating the conversion of spinel. On the other hand, the sintering schedule was improved by introducing a holding temperature gradient to promote the diffusion of Si 4+ and further promote the conversion of spinel into cordierite. With these methods, the residual spinel phase is minimized, the resulting high-purity cordierite has a 47% reduction in the thermal expansion coefficient from 3.07 × 10 −6 /K to 1.63 × 10 −6 /K compared to the original cordierite sample.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
Advances in Applied Ceramics
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2017
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IF 1.325
Yuanyuan Sun,Jingde Zhang,Shuaishuai Lu,Huichao Liu
Porous cordierite ceramics were synthesised by gel-casting method, using talcum powder, kaolin and alumina as raw materials. Organic monomers and cross-linker were used as additives. The phase composition and microstructure were investigated by X-ray diffraction and scanning electron microscope. The open porosity, compressive strength and thermal expansion coefficient were tested by the Archimedes method, universal testing machine and thermal expansion instrument, respectively. The results indicate that sintering temperature and holding time have a great influence on the cordierite properties. We obtain the good performance of porous cordierite ceramic sintering at 1350°C for 3 h. The cordierite phase content in the sample is higher and the crystallinity is better. At this point, the porosity is 58.53%, the compressive strength is 22.44 MPa and thermal expansion coefficient reaches 1.69 × 10−6 °C−1.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Lin Cao,Yuanyuan Wang,Xueqing Yu,Zhilun Lu,Ge Wang,Minmin Mao,Bing Liu,Lei Cao,Hadi Barzegar Bafrooei,Matjaz Spreitzer,Dawei Wang,Kaixin Song
Ultra-low permittivity ( ε r ：4–5) Mg 2 Al 4– x (Ge 0.5 Mg 0.5 ) x Si 5 O 18 (0.12 ≤ x ≤ 0.28) and Mg 2 Al 4– y (Mn 0.5 Mg 0.5 ) y Si 5 O 18 (0.1 ≤ y ≤ 0.3) cordierite ceramics were fabricated by solid-state reaction method. The improvement in [(Si 4 Al 2 )O 18 ] hexahedral ring roundness significantly enhances the quality factor through the substitution of complex ionic pairs of Ge 0.5 Mg 0.5 /Mn 0.5 Mg 0.5 for Al lattice sites in the [(Si 4 Al 2 )O 18 ] hexahedral ring of these cordierite ceramics. Excellent microwave dielectric performances of Mg 2 Al 3.8 (Ge 0.5 Mg 0.5 ) 0.2 Si 5 O 18 and Mg 2 Al 3.8 (Mn 0.5 Mg 0.5 ) 0.2 Si 5 O 18 ceramics sintered at 1400 °C were demonstrated using the Hakki-Coleman resonant method with ε r = 4.676, Q×f = 186, 503 [email protected] GHz and 199,476 GHz @ 27.434 GHz, τ f = −20.02 ppm/°C and ε r = 4.807, Q×f = 101,420 [email protected] GHz and 143,005 GHz @ 27.366 GHz, τ f = −26.44 ppm/°C, respectively. These results present the potential application of high-quality cordierite in future B5G/6 G millimeter and terahertz communication frequency bands.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
Frontiers in Chemistry
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2022
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IF 5.545
Li Yongfeng,Liao Qianyan,Ling Weizhao,Ye Fan,Liu Fangfang,Zhang Xipeng,He Jiajun,Cheng Gao
Exploring high-efficiency and stable monolithic structured catalysts is vital for catalytic combustion of volatile organic compounds. Herein, we prepared a series of Pd/δ-MnO2 nanoflower arrays monolithic integrated catalysts (0.01–0.07 wt% theoretical Pd loading) via the hydrothermal growth of δ-MnO2 nanoflowers onto the honeycomb cordierite, which subsequently served as the carrier for loading the Pd nanoparticles (NPs) through the electroless plating route. Moreover, we characterized the resulting monolithic integrated catalysts in detail and evaluated their catalytic activities for toluene combustion, in comparison to the controlled samples including only Pd NPs loading and the δ-MnO2 nanoflower arrays. Amongst all the monolithic samples, the Pd/δ-MnO2 nanoflower arrays monolithic catalyst with 0.05 wt% theoretical Pd loading delivered the best catalytic performance, reaching 90% toluene conversion at 221°C at a gas hourly space velocity (GHSV) of 10,000 h−1. Moreover, this sample displayed superior catalytic activity for o-xylene combustion under a GHSV of 10,000 h−1. The monolithic sample with optimal catalytic activity also displayed excellent catalytic stability after 30 h constant reaction at 210 and 221°C.
研究领域:
环境科学
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催化材料
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Lulu Wang,Beiyue Ma,Xinming Ren,Chao Yu,Chengji Deng,Chunming Liu,Chuanbo Hu
In an attempt to enhance the sintering and mechanical performance of porous cordierite ceramics (Mg 2 Al 4 Si 5 O 18 ) as support materials for vehicle exhaust catalysts, ZrO 2 and M x O y (M = La, Ce, and Nb) were simultaneously introduced into cordierite sintered at 1350 °C for 4 h. Then, the reinforced function of ZrO 2 and M x O y on the properties of porous cordierite ceramics was systematically evaluated, especially for the sample co-doped with ZrO 2 and La 2 O 3 . The results displayed a distinct enhancement in mechanical and thermal performance, and the cold compressive strength increased from 72.74 to 158.59 MPa as well as thermal conductivity ranged from 1.66 to 2.01 W m −1 K −1 , respectively. It is found that ZrO 2 facilitated activation sintering introduced via lattice distortion in cordierite and La 2 O 3 accelerated the formation of cordierite and ZrSiO 4 microcrystalline through the low-temperature liquid phase. The synergic effect between ZrO 2 and La 2 O 3 , therefore, had a significant role in the reinforced mechanical and thermal performance of porous cordierite ceramics. This work not only offers a feasible strengthening strategy, but also expands the possibilities for building high-performance structural and functional ceramics .
研究领域:
材料科学
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陶瓷工程
·
汽车工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
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IF 4.527
Yifan Du,Bolin Wen,Ronglu Shu,Liping Cao,Wei Wang
In this paper, potassium titanate whiskers was prepared via the Molten salt synthesis on the surface of cordierite ceramics for the regeneration of diesel particulate filters (DPFs). SEM, EDS , XRD , FT-IR, TG-DSC and TPO were carried out to characterize the morphology, microstructure, growth mechanism and catalytic performance of the samples. Potassium titanate whiskers with diameter (100–500 nm) and length (about 3 μm) is tightly combined with the cordierite ceramic substrate . The catalyst performance investigation demonstrates that potassium titanate whiskers decrease the soot combustion temperature apparently. The soot combustion process was studied by thermal analysis tests, and the activation energy of the combustion reaction can be calculated using Freeman-Carroll method. The carbon oxidation activation energy is 14.009 kcal/mol, and the activation energy for the catalytic reaction with potassium titanate whiskers is 6.287 kcal/mol, it can be illustrated that potassium titanate whiskers/cordierite catalyst possess excellence performance for carbon catalytic combustion. The coarseness of the interface increased because potassium titanate whiskers grew on the cordierite substrate, and the trapping ability could improve. This unique microstructure has potential application in the DPF field.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 52
·27259-27266
·
IF 3.708
Libin Yang,Feng Xin,Junzhong Lin,Zhuang Zhuang,Rui Sun
In this study, a hydrothermal synthesis was developed to prepare a thin titanium silicalite-1 catalyst layer in the internal channels of the honeycomb cordierite support, which was used in a continuous heterogeneous reaction. The as-prepared thin TS-1 catalyst layer was characterized by SEM, XRD, UV-vis and ATR-FTIR methods. Multiple hydrothermal syntheses were used for controlling the crystalline growth to optimize catalytic activity and lifetime. Moreover, a monolithic TS-1/cordierite reactor with external looping was utilized to investigate the characteristics of the continuous heterogeneous ammoximation reaction without the organic solvent tert-butanol (TBA). The reaction results showed that the conversion of cyclohexanone and selectivity of oxime approached more than 0.96 and 0.98, respectively. When compared with the reaction using TBA as the reaction solvent, the activity of the monolithic TS-1/cordierite showed no differences except for a longer lifetime.
研究领域:
化学工程
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催化化学
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材料科学
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工业化学
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绿色化学
✓ 已验证
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 24
·5550
·
IF 3.2
Xianpeng Huang,Na Wei,Fengshuang Wang,Xiaoli Zhang
Cordierite diesel particulate filters (DPFs) were prepared using pure cordierite powder with organic binders, sodium silicate aids and pore formers by extrusion technique. The orthogonal test method was adopted to investigate the optimal value of the multi-objective and multi-factor problems. Based on results from statistical analysis, sintering temperature is the most important factor. The optimal parameters for balanced overall performance were determined as a 3 h holding time, 10 wt.% pore former, 12 wt.% sintering aid, and a sintering temperature of 1150 °C, representing a compromise among the individually optimal conditions for porosity, compressive strength, and thermal shock resistance identified by range analysis. The sodium silicate liquid increased and viscosity decreased with the increasing of temperature, which led to the formation of glass phases and the improvement of density. Therefore, with increasing sintering temperature, the porosity and coefficient of thermal expansion decreased. Both the mechanical properties and chemical stability of the prepared samples are strengthened. When the sintering temperature was 1150 °C, the prepared samples with high porosity (56.04%), compressive strength (5.88 MPa), bending strength (13.10 MPa), and low thermal expansion coefficient (CTE, 1.82 × 10 −6 /°C) showed the best comprehensive performance of thermal shock resistance and filtration efficiency. These results demonstrate great potential for DPF applications and provide a reference for the design of other honeycomb ceramics with optimum level of liquid phase.
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产品关联
DOI
PubMed
高影响因子
CHEMICAL PAPERS
·
2024
·Vol. 78
·期 4
·2275-2285
·
IF 2.1
Shu Ronglu,Du Yifan,Cao Liping,Zhao Hui,Luo Xiaoying,Wang Wei
Cerium samarium oxides catalysts with K + doping on the wall surface of cordierite honeycomb ceramics were preparation by sol–gel and dipping processes. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform-infrared spectroscopy were used to characterize the structural morphology and phase compositions. Through XPS analysis and H 2 -TPR measurement of monolithic catalyst, it is found that potassium ions improve the oxygen mobility in CeO 2 lattice and form surface active oxygen, increase the amount of oxygen adsorbed on the surface and improve the oxidation–reduction capacity. The catalytic combustion research demonstrates that T 10 , T 50 and T m in samples (Ce/Sm-0 K, Ce/Sm-0.3 K, Ce/Sm-0.5 K and Ce/Sm-0.7 K) decrease significantly compared with the blank reference (Cordierite). And the optimized sample Ce/Sm-0.5 K possess the lowest T 10 (389.6 °C), the lowest T 50 (425.5 °C), and the lowest T m (419 °C) in comparison with other samples. The cycle stability investigation reveals that sample Ce/Sm-0.5 K has excellent structural stability and stable catalytic performance, which has potential application in soot catalytic combustion field.
研究领域:
催化化学
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材料科学
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环境工程
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化学工程
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表面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）