Ultrathin metalorganic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dime nsional (2D) features. Although many progresses have been achieved, it is still ...Ultrathin metalorganic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dime nsional (2D) features. Although many progresses have been achieved, it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets. Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness, in which PVP is reacted with 2-aminoterephthalic acid (H2BDC-NH2) via formation of C=N bon d, followed by coord inatio n with Ni2+ io ns to form the ultrathi n MOF n anosheets. Impressively, when used in the Kno eve nagel condensation reactions of propane dinitrile with different aldehydes, ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF, mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products.展开更多
Direct transformation of ethanol to ethyl acetate was investigated on a series of Cu（ZrO2）/SiO2 catalysts. Inductively coupled plasma（ICP）, surface area analysis, X-ray diffraction（XRD）, H2-temperature programme...Direct transformation of ethanol to ethyl acetate was investigated on a series of Cu（ZrO2）/SiO2 catalysts. Inductively coupled plasma（ICP）, surface area analysis, X-ray diffraction（XRD）, H2-temperature programmed reduc- tion（H2-TPR）, X-ray photoelectron spectroscopy（XPS）, NH3-temperature programmed desorption（NH3-TPD） and Fourier transform-infrared spectroscopy（FTIR） techniques were used to characterize the catalysts. The results reveal that ZrO2 can improve the dispersion of copper species and increase the acidity of the Cu（ZrO2）/SiO2 catalysts. The Cu0 is responsible for ethanol dehydrogenation to acetaldehyde, and both the Lewis acid and Bronsted acid sites were in favor of the selectivity to ethyl acetate. The synergistic effect of Cu0 and an appropriate amount of acidic sites played an important role in the production of ethyl acetate.展开更多
The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 1...The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity.展开更多
基金the National Key Basic Research Program of China (Nos. 2014CB931801 and 2016YFA0200700, Z. Y. T.)National Natural Science Foundation of China (Nos. 21890381, 21721002 and 21475029, Z. Y. T.+4 种基金21722102, 51672053 and 21303029, G. D. L.)Beijing Natural Science Foundation (No. 2182087, G. D. L.)Frontier Science Key Project of Chinese Academy of Sciences (No. QYZDJ-SSW-SLH038,Z. Y. T.)K. C. Wong Education Foundation (Z. Y T.)Youth Innovation Promotion Association CAS (No. 2016036, G. D. L.).
文摘Ultrathin metalorganic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dime nsional (2D) features. Although many progresses have been achieved, it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets. Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness, in which PVP is reacted with 2-aminoterephthalic acid (H2BDC-NH2) via formation of C=N bon d, followed by coord inatio n with Ni2+ io ns to form the ultrathi n MOF n anosheets. Impressively, when used in the Kno eve nagel condensation reactions of propane dinitrile with different aldehydes, ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF, mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products.
基金supported by the Natural Science Foundation of Jiangsu Province(BK2012347)the National Natural Science Foundation of China(51306034)the National Basic Research Program of China(973 Program,2013CB228505)~~
基金Supported by the Natural Science Foundation of Science and Technology Department of Jilin Province, China（No.20130101015JC）, the Open Project Supported by State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University, China （No.2012-15）, and the Innovation Project of Frontiers of Science and New Interdiscipline of Jilin University, China.
文摘Direct transformation of ethanol to ethyl acetate was investigated on a series of Cu（ZrO2）/SiO2 catalysts. Inductively coupled plasma（ICP）, surface area analysis, X-ray diffraction（XRD）, H2-temperature programmed reduc- tion（H2-TPR）, X-ray photoelectron spectroscopy（XPS）, NH3-temperature programmed desorption（NH3-TPD） and Fourier transform-infrared spectroscopy（FTIR） techniques were used to characterize the catalysts. The results reveal that ZrO2 can improve the dispersion of copper species and increase the acidity of the Cu（ZrO2）/SiO2 catalysts. The Cu0 is responsible for ethanol dehydrogenation to acetaldehyde, and both the Lewis acid and Bronsted acid sites were in favor of the selectivity to ethyl acetate. The synergistic effect of Cu0 and an appropriate amount of acidic sites played an important role in the production of ethyl acetate.
文摘The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity.
