The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether...The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether in a fixed-bed reactor under the same operating conditions （T = 300 ？C, P = 1 bar, LHSV = 2.8, 11.7, 26.1 h？1） and characterized by means of N2 adsorption-desorption, NH3-TPD, XRD, TGA and SEM techniques. According to the experimental results, the catalysts prepared using sol-gel method in non-aqueous medium showed better performance compared with those prepared by other methods.展开更多
Nanoparticle of cerium borate with a size of about 50 nm was synthesized via sol-gel precipitation method under micro-emulsion by oleic acid,using Na2B4O7 and Ce（NO3）3 aqueous solution as raw materials,and the morph...Nanoparticle of cerium borate with a size of about 50 nm was synthesized via sol-gel precipitation method under micro-emulsion by oleic acid,using Na2B4O7 and Ce（NO3）3 aqueous solution as raw materials,and the morphology and microstructure of as-prepared particles were characterized by means of scanning electron microscopy（SEM） equipped with an energy-dispersive X-ray spectrometer（EDS）,X-ray diffraction（XRD）,infrared spectroscopy（IR）,and thermogravimetric analysis（TGA）.Two methods to disperse the particles into base oil were employed,and the results derived from the four-ball tribotester indicated that the friction coefficient of the base oil by the addition of the nanoscale cerium borate particles diminished greatly,and the anti-wear properties also depended on the dispersion methods.展开更多
基金supported by Iranian Nanotechnology Initiative Council
文摘The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether in a fixed-bed reactor under the same operating conditions （T = 300 ？C, P = 1 bar, LHSV = 2.8, 11.7, 26.1 h？1） and characterized by means of N2 adsorption-desorption, NH3-TPD, XRD, TGA and SEM techniques. According to the experimental results, the catalysts prepared using sol-gel method in non-aqueous medium showed better performance compared with those prepared by other methods.
文摘Nanoparticle of cerium borate with a size of about 50 nm was synthesized via sol-gel precipitation method under micro-emulsion by oleic acid,using Na2B4O7 and Ce（NO3）3 aqueous solution as raw materials,and the morphology and microstructure of as-prepared particles were characterized by means of scanning electron microscopy（SEM） equipped with an energy-dispersive X-ray spectrometer（EDS）,X-ray diffraction（XRD）,infrared spectroscopy（IR）,and thermogravimetric analysis（TGA）.Two methods to disperse the particles into base oil were employed,and the results derived from the four-ball tribotester indicated that the friction coefficient of the base oil by the addition of the nanoscale cerium borate particles diminished greatly,and the anti-wear properties also depended on the dispersion methods.
