MICROPOROUS AND MESOPOROUS MATERIALS
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2019
·
IF 4.182
Ruyue Niu,Pengcheng Liu,Wei Li,Shuang Wang,Jinping Li
0.123%Pd encapsulated in nanosized silicalite-1 (MFI) zeolite catalysts has been prepared by direct hydrothermal conditions, and its catalytic performance at the low concentration methane combustion was studied. The temperatures for methane ignition ( T 10% ), the half-conversion temperature ( T 50% ) and the total conversion temperature ( T 90% ) over Pd/S-1-in (in-situ method) catalyst are 261, 329 and 382 °C, respectively, which are lower than the corresponding temperatures of Pd/S-1-im (incipient impregnation method) catalyst. Moreover, the properties are further enhanced by introducing CeO 2 into the Pd/S-1-in catalyst. The conversion rate decreased slightly from 91 to 85% when the reaction is carried out at 450 °C for 100 h at the gas hourly space velocities (GHSV) of 112500 mL g −1 h −1 . The XPS analysis showed that Pd clusters were encapsulated within the porous rather than on the surface of the crystal by in-situ method. The HRTEM studies demonstrated that the Pd particle encapsulated within Silicalite-1 zeolites are well dispersed and evenly distributed throughout the Silicalite-1 zeolites. The average size of in situ Pd particle encapsulated in Silicalite-1 zeolite is 1.7 nm, which is much smaller than the impregnated Pd/S-1-im catalyst (2.8 nm).
研究领域:
化学工程
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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
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 25
·期 2
·169-184
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IF 0
Li Yingxia,Li Jiaxin,Yang Xiao,Wang Xitao,Xu Yanhong,Zhang Lihong
A series of PtCuCeMgAl quintuple hydrotalcite-like compounds with different Ce contents were synthesized by one-pot method. After calcining and reduction, CeO 2 -modified Mg(Al)O-supported Pt–Cu alloy catalysts were obtained. To understand the effect of Cu and Ce, the structure and physico-chemistry properties of the catalysts were characterized and analyzed, and the catalytic behaviors were investigated in a direct dehydrogenation of propane to propene. The results show that the Pt 4+ , Cu 2+ , and Ce 3+ ions can be incorporated into the brucite-like layers and the Ce content significantly affects the interaction strength between Pt and Cu and the dehydrogenation performance of propane. Under the reaction conditions, the highest propane conversion (45%) with 89% selectivity to propene and a 40% propene yield were achieved with a 0.3 wt% Ce-modified PtCu/Mg(Al)O catalyst. The improved catalytic performance is related to the easy formation of Pt–Cu alloy phase, excellent resistance to sintering, and coke deposits of active components modified by CeO 2 .
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
JOURNAL OF THERMAL SPRAY TECHNOLOGY
·
2022
·Vol. 31
·期 8
·2463-2475
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IF 2.839
Liu Ji,Chen Tongzhou,Duan Haitao,Yuan Chengqing,Bai Xiuqin
Cavitation erosion is a major failure mode of hydraulic turbine components. Coatings could be an effective solution to this problem. In this study, a CeO2-modified (1 wt%) dual-scale WC-10Co-4Cr powder (WC composed of 70 wt% micrometer WC (2.5 μm) and 30 wt% nanometer WC (100 ~ 200 nm)) was fabricated by agglomeration and sintering. CeO2-modified dual-scale WC-10Co-4Cr coatings (C-coating), dual-scale WC-10Co-4Cr coatings (D-coating), and micrometer WC-10Co-4Cr coatings (M-coating) were then deposited using a high-velocity oxygen fuel (HVOF). The mechanical properties and cavitation erosion behavior of these coatings were studied. The results showed that the CeO2-modified WC-10Co-4Cr coatings could effectively reduce decarburization in the powder preparation and HVOF process, the coatings having the highest WC retention rate. The C-coatings possessed a higher fracture strength (6.3 MPa m 1/2 ) and hardness (1348.2 HV0.3) than the D-coatings by more than 8.6 and 3.0%, respectively. The cavitation erosion resistance of the WC-10Co-4Cr coatings was affected by their microstructure and mechanical properties. The CeO2-modified coatings exhibited improved fracture toughness and hardness, reduced porosity, and, as a result, the C-coatings had the best cavitation erosion resistance.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2015
·
IF 2.79
Shangzhe Sun,Ming Zhao,Liang Cai,Shuai Zhang,Dewang Zeng,Rui Xiao
The iron-based oxygen carrier with high oxygen transfer capacity has always been the key point in the chemical looping hydrogen generation (CLHG) process. In this study, CeO2-modified iron-based oxygen carriers with the porous reticular structure were prepared by the sol–gel method. Samples were tested in a thermogravimetric analyzer (TGA) and lab-scale fixed-bed reactor, respectively, to evaluate their capacities of hydrogen production and the resistance to carbon deposition or Fe3C formation. The effects of preparation conditions (CeO2 loading and [C6H8O7·H2O]/[PEG400] molar ratio) and experimental conditions (reducing atmosphere and temperature) on the physicochemical properties of CeO2-modified iron-based oxygen carriers were investigated. The initial screening test in TGA was done to select the samples with excellent reducibility and strong resistance to carbon deposition or Fe3C formation. Subsequent tests in the fixed-bed reactor were conducted to evaluate the redox characteristics and cyclic performance of the selected CeO2-modified samples. The results confirmed that iron-based oxygen carriers modified by CeO2 could effectively inhibit carbon deposition or Fe3C formation and the oxygen carrier prepared under the preparation conditions of Fe2O3/CeO2/Al2O3 = 65/5/30 and C6H8O7·H2O/PEG400 = 3 stood out from all the candidates by virtue of its high hydrogen production efficiency and the excellent recycle ability in the CLHG process. The oxygen carriers at the optimal reducing atmosphere (CO/H2/N2 = 40/30/30 and the steam oxidation reaction at 900 °C) showed the best performance with the highest hydrogen yield.
研究领域:
能源材料
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Water
·
2024
·Vol. 16
·期 5
·675
·
IF 3
Xiujuan Feng,Yanjun Zou,Sékou Mohamed Condé,Xiaoqing Wang,Chengliang Dong
Sulfate is a typical characteristic pollutant in mine water. Because of its high concentration and large discharge of mine water, it has become a difficult problem in mineral exploitation. Capacitive deionization (CDI) is an innovative and economical removal technology. There are few reports on the use of CDI to remove SO42−from mine water. In this study, a CeO2activated carbon electrode with good wettability, excellent electrochemical performance, and suitable pore structure was prepared by the sol-gel method. The application of the CeO2activated carbon electrode to the capacitive method for treating high SO42−mine water was investigated using simulated wastewater and actual mine water. The study structure shows that CeO2:activated carbon (AC) has the best wettability, the highest specific capacitance, and the lowest electrical conductivity when the mass ratio of CeO2is 5%. At 100 mg/L, the electrode has the maximum SO42−ion specific adsorption capacity (SAC). At 1 V and 20 mL/min, this value is measured. The electrode has a SAC value of 9.36 mg/g, far higher than the AC electrode’s 4.1 mg/g. The effect of CDI process factors such the voltage, flow rate, and initial concentration was studied to find the best treatment method. SAC retention is 91% after 10 adsorption–desorption cycles, demonstrating outstanding electrode performance. Under the best CDI process (1.4 volts, 30 mL/min), mine water was treated. After 20 cycles of treatment, the concentration of SO42−in mine water decreased from 1170 mg/L to 276.46 mg/L, and the removal rate was 76.37%. This study proved that the CeO2modified activated carbon electrode capacitance method can effectively remove sulfate ions and other ions from mine water.
研究领域:
环境科学
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材料科学
·
水处理工程
✓ 已验证
DOI
高影响因子
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