The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols （ethylene glycol, glycerol, xylitol, sorbitol and glucose）, were investigated by hydrogenation of naphthalene. Compare...The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols （ethylene glycol, glycerol, xylitol, sorbitol and glucose）, were investigated by hydrogenation of naphthalene. Compared with the conventional wetness impregnation, addition of moderate polyols into the metal nitrate support surface, resulting in formation of persion of the active phase and significant aqueous solution could enhance interaction with very small NiO particle size （〈5 nm）, high discatalytic activity. Particle size of Ni^0 decreased from 36.1 nm to below 5 nm; meanwhile the complete hydrogenation of naphthalene was dependent on the Ni^0 particle size. The hydrogenation activities of the catalysts prepared by co-impregnation with polyols were very high with 100% conversion even at iow temperature of 55 ℃.展开更多
The activity of Mo_(2) C-based catalyst on vegetable oil conversion into biofuel could be greatedly promoted by tuning the carbon content,while its modification mechanism on the surface properties remained elusive.Her...The activity of Mo_(2) C-based catalyst on vegetable oil conversion into biofuel could be greatedly promoted by tuning the carbon content,while its modification mechanism on the surface properties remained elusive.Herein,the exposed active sites,the particle size and Lewis acid amount of Ni-Mo_(2) C/MCM-41 catalysts were regulated by varying CH_(4) content in carbonization gas.The activity of Ni-Mo_(2) C/MCM-41 catalysts in jatropha oil(JO)conversion showed a volcano-like trend over the catalysts with increasing CH_(4) content from 15%to 50%in the preparation process.The one prepared by 25%CH_(4) content(NiMo_(2) C(25)/MCM-41)exhibited the outstanding catalytic performance with 83.9 wt%biofuel yield and95.2%C_(15)-C_(18) selectivity.Such a variation of activity was ascribed to the most exposed active sites,the smallest particle size,and the lowest Lewis acid amount from Ni^(0) on the Ni-Mo_(2) C(25)/MCM-41 catalyst surface.Moreover,the Ni-Mo_(2) C(25)/MCM-41 catalyst could also effectively catalyze the conversion of crude waste cooking oil(WCO)into green diesel.This study offers an effective strategy to improve catalytic performance of molybdenum carbide catalyst on vegetable oil conversion.展开更多
A series of Ni/AlMCM-41 catalysts with different nickel contents was prepared via the incipient wetness impregnation method. The effects of the nickel content on the structure, acidity and metal function of the cataly...A series of Ni/AlMCM-41 catalysts with different nickel contents was prepared via the incipient wetness impregnation method. The effects of the nickel content on the structure, acidity and metal function of the catalysts were studied by using different techniques. In the test of n-dodecane hydroconversion, it was found that the metal and acid functions were well balanced over a 2.0%Ni(mass fraction)/AlMCM-41 catalyst, which gave the maximal isomerization selectivity and a homolytic cleavage products.展开更多
Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate tempe...Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate temperature range from 400°C to 600°C and the catalytic activity of the catalysts remains stable during 500 min steam on time. CNTs were chiefly formed through tip-growth mode, due to the weak interaction between the metallic Ni and the support. Most of the Ni particles are located on the tip of the produced CNTs, which avoids rapid deactivation of the catalyst resulted from carbon encapsulation. Large Ni particles usually lead to the formation of CNTs with big diameter. During the reaction, the shape of Ni particles changed from pseudo-sphere to diamond-like. All the CNTs consist of multiple layer walls and are curved in certain degree.展开更多
Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/...Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/AI = 50, using CTAB （cetyltrimethylammonium bromide） as a template, and TMAOH （tetramethylammonium hydroxide） as co-surfactant, where a hydrothermal process at 100 ℃ was conducted for 12 h. Organic compounds were then burned out from the dry solid material by calcination at 540 ℃. Ni/MCM-41 and H-MCM-41 were produced by ion exchange method, followed by reduction and calcination treatments, respectively, while NiMo/MCM-41 was produced by impregnation method followed by calcination. Product of MCM-41 was characterized by XRD （X-ray Diffraction）, Fourier FTIR （transform infra red spectrophotometric）, TEM （transmission electron microscopic） and BET （brunauer-emmet-teller） methods. Performance of the catalytic activities were shown by both of NiMo/MCM-41 and the mixture of 1：1 of H-MCM-41 and Ni/MCM-41 were mixed with the ULO at ratio of 1：200 （w/v） in a stainless steel reactor, then they were heated at 420 ℃. The products of cracking were analyzed using GC-MS （gas chromatography-mass spectrometry）. Results of the work showed that the MCM-41 was successfully synthesized. Using mixture of Ni/MCM-41 and H-MCM-41 catalysts, 56.6% of ULO could be converted to OLP （organic liquid product）. However, using NiMo/MCM-41 catalyst only 28.5% OLP could be produced. GC-MS analyses showed that cracking of the ULO at 420 ~C using NiMo/MCM-41 catalyst gave conversion 4.3% and 8.8% to gasoline like and diesel like fractions, respectively, while using mixture of Ni/MCM-41 and H-MCM-41 catalysts, conversion of 12.2% and 14.8% respectively to gasoline like and diesel like fractions were obtained.展开更多
基金V. ACKNOWLEDGMENTS This work was supported by the National High-Tech Research and Development 863 Program of China （No.2012AA101806）, the National Natural Science Foundation of China （No.21306195 and No.51276183）, and the National Key Basic Research Program 973 Project from Ministry of Science and Technology of China （No.2012CB215304）.
文摘The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols （ethylene glycol, glycerol, xylitol, sorbitol and glucose）, were investigated by hydrogenation of naphthalene. Compared with the conventional wetness impregnation, addition of moderate polyols into the metal nitrate support surface, resulting in formation of persion of the active phase and significant aqueous solution could enhance interaction with very small NiO particle size （〈5 nm）, high discatalytic activity. Particle size of Ni^0 decreased from 36.1 nm to below 5 nm; meanwhile the complete hydrogenation of naphthalene was dependent on the Ni^0 particle size. The hydrogenation activities of the catalysts prepared by co-impregnation with polyols were very high with 100% conversion even at iow temperature of 55 ℃.
基金financially supported by the National Natural Science Foundation of China(No.21972099)the National Natural Science Foundation of China(National Special Scientific Research Instrument and Equipment Development)(No.21427803-2)the 111 project(No.B17030)。
文摘The activity of Mo_(2) C-based catalyst on vegetable oil conversion into biofuel could be greatedly promoted by tuning the carbon content,while its modification mechanism on the surface properties remained elusive.Herein,the exposed active sites,the particle size and Lewis acid amount of Ni-Mo_(2) C/MCM-41 catalysts were regulated by varying CH_(4) content in carbonization gas.The activity of Ni-Mo_(2) C/MCM-41 catalysts in jatropha oil(JO)conversion showed a volcano-like trend over the catalysts with increasing CH_(4) content from 15%to 50%in the preparation process.The one prepared by 25%CH_(4) content(NiMo_(2) C(25)/MCM-41)exhibited the outstanding catalytic performance with 83.9 wt%biofuel yield and95.2%C_(15)-C_(18) selectivity.Such a variation of activity was ascribed to the most exposed active sites,the smallest particle size,and the lowest Lewis acid amount from Ni^(0) on the Ni-Mo_(2) C(25)/MCM-41 catalyst surface.Moreover,the Ni-Mo_(2) C(25)/MCM-41 catalyst could also effectively catalyze the conversion of crude waste cooking oil(WCO)into green diesel.This study offers an effective strategy to improve catalytic performance of molybdenum carbide catalyst on vegetable oil conversion.
基金the Funds for the National Key Fundamental Research and Developm ent Projects of China (No.G19990 2 2 4 0 2 )
文摘A series of Ni/AlMCM-41 catalysts with different nickel contents was prepared via the incipient wetness impregnation method. The effects of the nickel content on the structure, acidity and metal function of the catalysts were studied by using different techniques. In the test of n-dodecane hydroconversion, it was found that the metal and acid functions were well balanced over a 2.0%Ni(mass fraction)/AlMCM-41 catalyst, which gave the maximal isomerization selectivity and a homolytic cleavage products.
文摘Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate temperature range from 400°C to 600°C and the catalytic activity of the catalysts remains stable during 500 min steam on time. CNTs were chiefly formed through tip-growth mode, due to the weak interaction between the metallic Ni and the support. Most of the Ni particles are located on the tip of the produced CNTs, which avoids rapid deactivation of the catalyst resulted from carbon encapsulation. Large Ni particles usually lead to the formation of CNTs with big diameter. During the reaction, the shape of Ni particles changed from pseudo-sphere to diamond-like. All the CNTs consist of multiple layer walls and are curved in certain degree.
文摘Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/AI = 50, using CTAB （cetyltrimethylammonium bromide） as a template, and TMAOH （tetramethylammonium hydroxide） as co-surfactant, where a hydrothermal process at 100 ℃ was conducted for 12 h. Organic compounds were then burned out from the dry solid material by calcination at 540 ℃. Ni/MCM-41 and H-MCM-41 were produced by ion exchange method, followed by reduction and calcination treatments, respectively, while NiMo/MCM-41 was produced by impregnation method followed by calcination. Product of MCM-41 was characterized by XRD （X-ray Diffraction）, Fourier FTIR （transform infra red spectrophotometric）, TEM （transmission electron microscopic） and BET （brunauer-emmet-teller） methods. Performance of the catalytic activities were shown by both of NiMo/MCM-41 and the mixture of 1：1 of H-MCM-41 and Ni/MCM-41 were mixed with the ULO at ratio of 1：200 （w/v） in a stainless steel reactor, then they were heated at 420 ℃. The products of cracking were analyzed using GC-MS （gas chromatography-mass spectrometry）. Results of the work showed that the MCM-41 was successfully synthesized. Using mixture of Ni/MCM-41 and H-MCM-41 catalysts, 56.6% of ULO could be converted to OLP （organic liquid product）. However, using NiMo/MCM-41 catalyst only 28.5% OLP could be produced. GC-MS analyses showed that cracking of the ULO at 420 ~C using NiMo/MCM-41 catalyst gave conversion 4.3% and 8.8% to gasoline like and diesel like fractions, respectively, while using mixture of Ni/MCM-41 and H-MCM-41 catalysts, conversion of 12.2% and 14.8% respectively to gasoline like and diesel like fractions were obtained.
