A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The struct...A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.展开更多
SiCp/Al2O3-Al composites were synthesized by means of direct metal oxidation method. The composition and microstructures of the composites were investigated using X-ray diffraction （XRD）, scanning electron microsco...SiCp/Al2O3-Al composites were synthesized by means of direct metal oxidation method. The composition and microstructures of the composites were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） and metallurgical microscope. The effects of technical parameters on the properties of the product were analyzed. The results indicate that the composite possesses a dense microstructure, composed of three interpenetrated phases. Of them, SiO2 layer prohibits the powdering of the composites; Mg promotes the wetting and infiltration of the system and Si restricts the interfacial reaction while improving the wetting ability between reinforcement and matrix.展开更多
Metal matrix composites (MMCs) are gaining widespread recognition in numerous technological fields owing to its superior mechanical properties when compared with conventional metals/alloys. The aluminium based hybrid ...Metal matrix composites (MMCs) are gaining widespread recognition in numerous technological fields owing to its superior mechanical properties when compared with conventional metals/alloys. The aluminium based hybrid composites are increasingly being used in the transport, aerospace, marine, automobile and mineral processing industries, owing to the improved strength, stiffness and wear resistance properties. In the present research work, the composites were prepared using the liquid metallurgy technique, in which 2 - 10 weight percentage of Al2O3 particulates and 1 weight percentage of Graphite were dispersed in the base Al6061 alloy. The Casted hybrid composites were subjected to machining process to prepare the specimens according to ASTM standards. Then, the prepared specimens are subjected for assessing the Microstructure followed by its Mechanical behaviors such as, Hardness, Tensile strength, Compressive strength respectively. The microstructure analysis confirms that homogenous distribution of Al2O3 and Gr in the Al6061 matrix alloy and there was a momentous enhancement in decisive tensile strength, compressive strength and hardness properties of the hybrid composite. However, a substantial increase in the compressive strength was noticed in graphite reinforced composites as the graphite content was increased and there was a significant diminution in hardness coupled with monotonic increases in the ductility. Further, the ultimate tensile strength and compressive strength of the composite was noticed;thus the outcome of the study will provide explicit rationalizations for these observable facts. Therefore, the proposed way out in the study can provide ample of approaches to minimize the existing problem by employing this newer hybrid composites.展开更多
A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonate...A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.展开更多
Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption,...Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.展开更多
Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing...Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing agent(LCDA) induced method. No template was needed throughout the synthesis processes. The structure and porosity of zeolite composites were analyzed by means of X-ray powder diffraction(XRD), scanning electron microscopy(SEM) and N_2adsorption-desorption isotherms. The results showed that the supported zeolite composites with varied zeolitic crystalline phases and different morphologies can be obtained by adjusting the crystallization parameters, such as the crystallization temperature, the composition and the alkalinity of the precursor solution. The presence of LCDA was defined as a determinant for synthesizing the zeolite composites. The mechanisms for formation of the hierarchically porous FAU zeolite composites in the LCDA induced synthesis process were discussed. The resulting monolithic zeolite with a trimodal-porous hierarchical structure shows potential applicability where facile diffusion is required.展开更多
A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was emplo...A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2 nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3.展开更多
基金supported by the National Natural Science Foundation of China(21377018)the Natural Science Foundation of Liaoning Province of China(2013020116)the Fundamental Research Funds for the Central Universities(DUT15ZD240)~~
文摘A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.
基金National Natural Science Foundation of China (50372037)Scientific Research Foundations of Shaanxi University of Science and Technology (SUST-B14)
文摘SiCp/Al2O3-Al composites were synthesized by means of direct metal oxidation method. The composition and microstructures of the composites were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） and metallurgical microscope. The effects of technical parameters on the properties of the product were analyzed. The results indicate that the composite possesses a dense microstructure, composed of three interpenetrated phases. Of them, SiO2 layer prohibits the powdering of the composites; Mg promotes the wetting and infiltration of the system and Si restricts the interfacial reaction while improving the wetting ability between reinforcement and matrix.
文摘Metal matrix composites (MMCs) are gaining widespread recognition in numerous technological fields owing to its superior mechanical properties when compared with conventional metals/alloys. The aluminium based hybrid composites are increasingly being used in the transport, aerospace, marine, automobile and mineral processing industries, owing to the improved strength, stiffness and wear resistance properties. In the present research work, the composites were prepared using the liquid metallurgy technique, in which 2 - 10 weight percentage of Al2O3 particulates and 1 weight percentage of Graphite were dispersed in the base Al6061 alloy. The Casted hybrid composites were subjected to machining process to prepare the specimens according to ASTM standards. Then, the prepared specimens are subjected for assessing the Microstructure followed by its Mechanical behaviors such as, Hardness, Tensile strength, Compressive strength respectively. The microstructure analysis confirms that homogenous distribution of Al2O3 and Gr in the Al6061 matrix alloy and there was a momentous enhancement in decisive tensile strength, compressive strength and hardness properties of the hybrid composite. However, a substantial increase in the compressive strength was noticed in graphite reinforced composites as the graphite content was increased and there was a significant diminution in hardness coupled with monotonic increases in the ductility. Further, the ultimate tensile strength and compressive strength of the composite was noticed;thus the outcome of the study will provide explicit rationalizations for these observable facts. Therefore, the proposed way out in the study can provide ample of approaches to minimize the existing problem by employing this newer hybrid composites.
基金Supported by the National Natural Science Foundation of China(21276076)the Fundamental Research Funds for the Central Universities of China(WA1014003)State Key Laboratory of Chemical Engineering(SKL-ChE-10C06)
文摘A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.
基金Project supported by National Natural Science Foundation of China (20773090, 20803049)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026, 200806100009)
文摘Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.
基金the financial support from the National Natural Science Foundation of China(No.20973022 and No.11472048)the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)(Serial No.33600000-14-ZC0607-0006)
文摘Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing agent(LCDA) induced method. No template was needed throughout the synthesis processes. The structure and porosity of zeolite composites were analyzed by means of X-ray powder diffraction(XRD), scanning electron microscopy(SEM) and N_2adsorption-desorption isotherms. The results showed that the supported zeolite composites with varied zeolitic crystalline phases and different morphologies can be obtained by adjusting the crystallization parameters, such as the crystallization temperature, the composition and the alkalinity of the precursor solution. The presence of LCDA was defined as a determinant for synthesizing the zeolite composites. The mechanisms for formation of the hierarchically porous FAU zeolite composites in the LCDA induced synthesis process were discussed. The resulting monolithic zeolite with a trimodal-porous hierarchical structure shows potential applicability where facile diffusion is required.
文摘A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2 nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3.
