The Experts below are selected from a list of 448407 Experts worldwide ranked by ideXlab platform
Hongmin Duan - One of the best experts on this subject based on the ideXlab platform.
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efficient aerobic oxidation of biomass derived 5 hydroxymethylfurfural to 2 5 diformylfuran catalyzed by magnetic nanoparticle supported manganese oxide
Applied Catalysis A-general, 2014Co-Authors: Zehui Zhang, Kangle Lv, Kejian Deng, Hongmin DuanAbstract:Abstract Magnetic Fe3O4 supported Mn3O4 nanoparticles (Fe3O4/Mn3O4) were prepared by the solvent Thermal Method, and its structure was characterized by XRD, XPS, TEM, and FT-IR technologies. The resulting Fe3O4/Mn3O4 nanoparticles could be used as an excellent heterogeneous catalyst for the aerobic oxidation of the biomass-derived model molecule 5-hydroxymethylfurfural into 2,5-diformylfuran (DFF) under benign reaction conditions. Some important reaction parameters such as reaction temperature, catalyst amount, solvent, oxidant, and oxygen pressure were explored and high DFF yield of 82.1% with HMF conversion of 100% were obtained in DMF under optimal reaction conditions. More importantly, the catalyst could be readily separated from the reaction mixture by a permanent magnet, and recycled up to 6 times without the significant loss of its catalytic activity.
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efficient aerobic oxidation of biomass derived 5 hydroxymethylfurfural to 2 5 diformylfuran catalyzed by magnetic nanoparticle supported manganese oxide
Applied Catalysis A-general, 2014Co-Authors: Bing Liu, Zehui Zhang, Kejian Deng, Hongmin DuanAbstract:Magnetic fe3o4 supported mn3o4 nanoparticles (fe3o4/mn3o4) were prepared by the solvent Thermal Method, and its structure was characterized by xrd, xi's, tem, and ft-ir technologies. the resulting fe3o4/mn3o4 nanoparticles could be used as an excellent heterogeneous catalyst for the aerobic oxidation of the biomass-derived model molecule 5-hydroxymethylfurfural into 2,5-diformylfuran (dff) under benign reaction conditions. some important reaction parameters such as reaction temperature, catalyst amount, solvent, oxidant, and oxygen pressure were explored and high dff yield of 82.1% with hmf conversion of 100% were obtained in dmf under optimal reaction conditions. more importantly, the catalyst could be readily separated from the reaction mixture by a permanent magnet, and recycled up to 6 times without the significant loss of its catalytic activity. (c) 2013 elsevier b.v. all rights reserved.
Mingjun Yang - One of the best experts on this subject based on the ideXlab platform.
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heat transfer analysis of methane hydrate sediment dissociation in a closed reactor by a Thermal Method
Energies, 2012Co-Authors: Jiafei Zhao, Chuanxiao Cheng, Yongchen Song, Zhi Yang, Dayong Wang, Mingjun YangAbstract:The heat transfer analysis of hydrate-bearing sediment involved phase changes is one of the key requirements of gas hydrate exploitation techniques. In this paper, experiments were conducted to examine the heat transfer performance during hydrate formation and dissociation by a Thermal Method using a 5L volume reactor. This study simulated porous media by using glass beads of uniform size. Sixteen platinum resistance thermometers were placed in different position in the reactor to monitor the temperature differences of the hydrate in porous media. The influence of production temperature on the production time was also investigated. Experimental results show that there is a delay when hydrate decomposed in the radial direction and there are three stages in the dissociation period which is influenced by the rate of hydrate dissociation and the heat flow of the reactor. A significant temperature difference along the radial direction of the reactor was obtained when the hydrate dissociates and this phenomenon could be enhanced by raising the production temperature. In addition, hydrate dissociates homogeneously and the temperature difference is much smaller than the other conditions when the production temperature is around the 10 °C. With the increase of the production temperature, the maximum of Δ T oi grows until the temperature reaches 40 °C. The period of Δ T oi have a close relation with the total time of hydrate dissociation. Especially, the period of Δ T oi with production temperature of 10 °C is twice as much as that at other temperatures. Under these experimental conditions, the heat is mainly transferred by conduction from the dissociated zone to the dissociating zone and the production temperature has little effect on the convection of the water in the porous media.
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heat transfer analysis of methane hydrate sediment dissociation in a closed reactor by a Thermal Method
Energies, 2012Co-Authors: Jiafei Zhao, Chuanxiao Cheng, Yongchen Song, Zhi Yang, Dayong Wang, Weiguo Liu, Yu Liu, Kaihua Xue, Zihao Zhu, Mingjun YangAbstract:The heat transfer analysis of hydrate-bearing sediment involved phase changes is one of the key requirements of gas hydrate exploitation techniques. In this paper, experiments were conducted to examine the heat transfer performance during hydrate formation and dissociation by a Thermal Method using a 5L volume reactor. This study simulated porous media by using glass beads of uniform size. Sixteen platinum resistance thermometers were placed in different position in the reactor to monitor the temperature differences of the hydrate in porous media. The influence of production temperature on the production time was also investigated. Experimental results show that there is a delay when hydrate decomposed in the radial direction and there are three stages in the dissociation period which is influenced by the rate of hydrate dissociation and the heat flow of the reactor. A significant temperature difference along the radial direction of the reactor was obtained when the hydrate dissociates and this phenomenon could be enhanced by raising the production temperature. In addition, hydrate dissociates homogeneously and the temperature difference is much smaller than the other conditions when the production temperature is around the 10 °C. With the increase of the production temperature, the maximum of Δ T oi grows until the temperature reaches 40 °C. The period of Δ T oi have a close relation with the total time of hydrate dissociation. Especially, the period of Δ T oi with production temperature of 10 °C is twice as much as that at other temperatures. Under these experimental conditions, the heat is mainly transferred by conduction from the dissociated zone to the dissociating zone and the production temperature has little effect on the convection of the water in the porous media.
Zehui Zhang - One of the best experts on this subject based on the ideXlab platform.
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efficient aerobic oxidation of biomass derived 5 hydroxymethylfurfural to 2 5 diformylfuran catalyzed by magnetic nanoparticle supported manganese oxide
Applied Catalysis A-general, 2014Co-Authors: Zehui Zhang, Kangle Lv, Kejian Deng, Hongmin DuanAbstract:Abstract Magnetic Fe3O4 supported Mn3O4 nanoparticles (Fe3O4/Mn3O4) were prepared by the solvent Thermal Method, and its structure was characterized by XRD, XPS, TEM, and FT-IR technologies. The resulting Fe3O4/Mn3O4 nanoparticles could be used as an excellent heterogeneous catalyst for the aerobic oxidation of the biomass-derived model molecule 5-hydroxymethylfurfural into 2,5-diformylfuran (DFF) under benign reaction conditions. Some important reaction parameters such as reaction temperature, catalyst amount, solvent, oxidant, and oxygen pressure were explored and high DFF yield of 82.1% with HMF conversion of 100% were obtained in DMF under optimal reaction conditions. More importantly, the catalyst could be readily separated from the reaction mixture by a permanent magnet, and recycled up to 6 times without the significant loss of its catalytic activity.
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efficient aerobic oxidation of biomass derived 5 hydroxymethylfurfural to 2 5 diformylfuran catalyzed by magnetic nanoparticle supported manganese oxide
Applied Catalysis A-general, 2014Co-Authors: Bing Liu, Zehui Zhang, Kejian Deng, Hongmin DuanAbstract:Magnetic fe3o4 supported mn3o4 nanoparticles (fe3o4/mn3o4) were prepared by the solvent Thermal Method, and its structure was characterized by xrd, xi's, tem, and ft-ir technologies. the resulting fe3o4/mn3o4 nanoparticles could be used as an excellent heterogeneous catalyst for the aerobic oxidation of the biomass-derived model molecule 5-hydroxymethylfurfural into 2,5-diformylfuran (dff) under benign reaction conditions. some important reaction parameters such as reaction temperature, catalyst amount, solvent, oxidant, and oxygen pressure were explored and high dff yield of 82.1% with hmf conversion of 100% were obtained in dmf under optimal reaction conditions. more importantly, the catalyst could be readily separated from the reaction mixture by a permanent magnet, and recycled up to 6 times without the significant loss of its catalytic activity. (c) 2013 elsevier b.v. all rights reserved.
Yuan Zhang - One of the best experts on this subject based on the ideXlab platform.
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porous corundum type in2o3 nanoflowers controllable synthesis enhanced ethanol sensing properties and response mechanism
CrystEngComm, 2015Co-Authors: Liping Gao, Fumin Ren, Zhixuan Cheng, Yuan Zhang, Qun XiangAbstract:Porous rhombohedral In2O3 (corundum-type In2O3, rh-In2O3) with a morphology of uniform nanoflowers was fabricated by using a mild, facile solvent-Thermal Method. The formation mechanism and transformation of phase were studied. The results revealed that the precursors were transformed from In(OH)3 to InOOH with an increase in reaction time. The phase transformation was attributed to the stability of the InOOH phase at small crystal volume, less water molecules and small pH value, which in turn led to the formation of metastable rh-In2O3. The optimal working temperature of the sensor based on porous rh-In2O3 nanoflowers was proved to be 280 °C, corresponding to chemisorbed oxygen analysis based on a temperature changeable XPS, further demonstrating the surface resistance controlled gas sensing mechanism of In2O3. The sensor exhibited an enhanced response and rapid response/recovery toward ethanol vapour, which was ascribed to hierarchical porous structures and more active defects.
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porous corundum type in2o3 nanosheets synthesis and no2 sensing properties
Sensors and Actuators B-chemical, 2015Co-Authors: Liping Gao, Zhixuan Cheng, Qun Xiang, Yuan ZhangAbstract:Abstract Porous corundum-type In2O3 (rhombohedra In2O3, rh-In2O3) nanosheets with unique shoeprint morphology are fabricated successfully by a facile, template-free solvent-Thermal Method. The products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and N2 adsorption–desorption. The response of the porous rh-In2O3 nanosheets sensor to 50 ppm NO2 is about 164, and the response/recovery times are not exceeding 5 s and 14 s, respectively. Porous lamellar structure could increase the number of the active sites and speed up the gas transportation, which is helpful for the enhancement of the response and rapid adsorption/desorption. The effect of morphology on the gas sensing responses is investigated. Compared with the nonporous rh-In2O3 nanosheets sensor, the porous rh-In2O3 nanosheets sensor exhibits significantly enhanced sensing performances toward NO2. Porous rh-In2O3 nanosheets sensors show a long-term stability, which might be ascribed to the avoidance of aggregation of the nanostructures.
Qun Xiang - One of the best experts on this subject based on the ideXlab platform.
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porous corundum type in2o3 nanoflowers controllable synthesis enhanced ethanol sensing properties and response mechanism
CrystEngComm, 2015Co-Authors: Liping Gao, Fumin Ren, Zhixuan Cheng, Yuan Zhang, Qun XiangAbstract:Porous rhombohedral In2O3 (corundum-type In2O3, rh-In2O3) with a morphology of uniform nanoflowers was fabricated by using a mild, facile solvent-Thermal Method. The formation mechanism and transformation of phase were studied. The results revealed that the precursors were transformed from In(OH)3 to InOOH with an increase in reaction time. The phase transformation was attributed to the stability of the InOOH phase at small crystal volume, less water molecules and small pH value, which in turn led to the formation of metastable rh-In2O3. The optimal working temperature of the sensor based on porous rh-In2O3 nanoflowers was proved to be 280 °C, corresponding to chemisorbed oxygen analysis based on a temperature changeable XPS, further demonstrating the surface resistance controlled gas sensing mechanism of In2O3. The sensor exhibited an enhanced response and rapid response/recovery toward ethanol vapour, which was ascribed to hierarchical porous structures and more active defects.
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porous corundum type in2o3 nanosheets synthesis and no2 sensing properties
Sensors and Actuators B-chemical, 2015Co-Authors: Liping Gao, Zhixuan Cheng, Qun Xiang, Yuan ZhangAbstract:Abstract Porous corundum-type In2O3 (rhombohedra In2O3, rh-In2O3) nanosheets with unique shoeprint morphology are fabricated successfully by a facile, template-free solvent-Thermal Method. The products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and N2 adsorption–desorption. The response of the porous rh-In2O3 nanosheets sensor to 50 ppm NO2 is about 164, and the response/recovery times are not exceeding 5 s and 14 s, respectively. Porous lamellar structure could increase the number of the active sites and speed up the gas transportation, which is helpful for the enhancement of the response and rapid adsorption/desorption. The effect of morphology on the gas sensing responses is investigated. Compared with the nonporous rh-In2O3 nanosheets sensor, the porous rh-In2O3 nanosheets sensor exhibits significantly enhanced sensing performances toward NO2. Porous rh-In2O3 nanosheets sensors show a long-term stability, which might be ascribed to the avoidance of aggregation of the nanostructures.
