A series of Al‐containing mesostructured cellular silica foams(Al‐MCFs)with different Si/Al molar ratios(x;x=10,20,30,40,or50)were prepared by a post synthetic method using aluminum isopropoxide as an alumina source...A series of Al‐containing mesostructured cellular silica foams(Al‐MCFs)with different Si/Al molar ratios(x;x=10,20,30,40,or50)were prepared by a post synthetic method using aluminum isopropoxide as an alumina source.The corresponding NiMo catalysts supported on Al‐MCFs were prepared and evaluated using dibenzothiophene(DBT)as the probe reactant.All the synthesized samples were characterized by small‐angle X‐ray scattering,scanning electron microscopy,nitrogen adsorption‐desorption,UV‐Vis diffuse reflectance spectroscopy,H2temperature‐programmed reduction,27Al MAS NMR,temperature‐programmed desorption of ammonia,pyridine‐FTIR,Raman spectroscopy,HRTEM,and X‐ray photoelectron spectroscopy to analyze their physicochemical properties and to gain a deeper insight of the interrelationship between the structures and the catalytic performance.The synthesis mechanism was proposed to involve the formation of Br?nsted acid and Lewis acid sites through the replacement of Si4+with Al3+.Aluminum introduced into MCFs by the post synthetic method has a negligible influence on the mesostructure of the parent MCFs but can form silicoaluminate materials with moderate Br?nsted acidity.For Al‐MCFs(x)materials,the detection of tetrahedrally coordinated Al3+cations demonstrated that the Al species had been successfully incorporated into the silicon frameworks.Furthermore,the DBT hydrodesulfurization(HDS)catalytic activity of the NiMo/Al‐MCFs(x)catalysts increased with increasing Si/Al molar ratio,and reached a maximum at a Si/Al molar ratio of20.The interaction of Ni and Mo species with the support became stronger when Al was incorporated into the MCFs supports.The high activities of the NiMo/Al‐MCFs catalysts for the DBT HDS were attributed to the suitable acidity properties and good dispersions of the Ni and Mo active phases.展开更多
文摘文章采用巯基丙基三甲氧基硅烷(MPTMS)对介孔泡沫二氧化硅(mesocellular silica foam,MCF)进行接枝磺化,制备了Pr-SO3H/MCF固体酸催化剂,并考察了苯基三甲氧基硅烷疏水改性对苯甲酸甲酯合成的影响。采用氮气吸附脱附(BET)、透射电子显微镜(transmission electron microscope,TEM)、接触角、元素分析仪等手段对催化剂进行表征。结果表明,苯基三甲氧基硅烷改性后的Ph/Pr-SO3H/MCF催化剂,比表面积略有降低,疏水性明显提高。由于苯环与苯环之间形成π-π键,增加了对反应物苯甲酸的吸附能力,在催化剂表面形成了高浓度苯甲酸微区,从而增加了酯化反应速率。同时由于表面的疏水性使得副产物水快速排出催化剂表面,避免催化剂水合,提高了催化剂的耐水性及稳定性。
基金Supported by the National Basic Research Program of China (973 Program,2006CB806103)the National Natural Science Foundation of China (20773027,20633030)the Shanghai Research Institute of Petrochemical Technology,and the Science and Technology Commission of Shanghai Municipality (08DZ2270500)
基金supported by National Natural Science Foundation of China (21276277,U1463207)CNOOC Project+1 种基金CNPC major projectthe Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology (2015K003)~~
文摘A series of Al‐containing mesostructured cellular silica foams(Al‐MCFs)with different Si/Al molar ratios(x;x=10,20,30,40,or50)were prepared by a post synthetic method using aluminum isopropoxide as an alumina source.The corresponding NiMo catalysts supported on Al‐MCFs were prepared and evaluated using dibenzothiophene(DBT)as the probe reactant.All the synthesized samples were characterized by small‐angle X‐ray scattering,scanning electron microscopy,nitrogen adsorption‐desorption,UV‐Vis diffuse reflectance spectroscopy,H2temperature‐programmed reduction,27Al MAS NMR,temperature‐programmed desorption of ammonia,pyridine‐FTIR,Raman spectroscopy,HRTEM,and X‐ray photoelectron spectroscopy to analyze their physicochemical properties and to gain a deeper insight of the interrelationship between the structures and the catalytic performance.The synthesis mechanism was proposed to involve the formation of Br?nsted acid and Lewis acid sites through the replacement of Si4+with Al3+.Aluminum introduced into MCFs by the post synthetic method has a negligible influence on the mesostructure of the parent MCFs but can form silicoaluminate materials with moderate Br?nsted acidity.For Al‐MCFs(x)materials,the detection of tetrahedrally coordinated Al3+cations demonstrated that the Al species had been successfully incorporated into the silicon frameworks.Furthermore,the DBT hydrodesulfurization(HDS)catalytic activity of the NiMo/Al‐MCFs(x)catalysts increased with increasing Si/Al molar ratio,and reached a maximum at a Si/Al molar ratio of20.The interaction of Ni and Mo species with the support became stronger when Al was incorporated into the MCFs supports.The high activities of the NiMo/Al‐MCFs catalysts for the DBT HDS were attributed to the suitable acidity properties and good dispersions of the Ni and Mo active phases.
