In industrial catalytic processes,coke deposition can cause catalyst deactivation by covering acid sites and/or blocking pores.The regeneration of deactivated catalysts,thereby removing the coke and simultaneously res...In industrial catalytic processes,coke deposition can cause catalyst deactivation by covering acid sites and/or blocking pores.The regeneration of deactivated catalysts,thereby removing the coke and simultaneously restoring the catalytic activity,is highly desired.Despite various chemical reactions and methods are available to remove coke,developing reliable,efficient,and economic regeneration methods for catalytic processes still remains a challenge in industrial practice.In this paper,the current progress of regeneration methods such as oxidation(air,ozone and oxynitride),gasification(carbon dioxide and water steam),and hydrogenation(hydrogen)is reviewed,which hopefully can shed some light on the design and optimization of catalysts and the related processes.展开更多
Biomass is considered the largest renewable energy source and an important alternative for biofuel production. The fast pyrolysis of biomass is an economical and advantageous to get bio-oil. However, bio-oil has a lar...Biomass is considered the largest renewable energy source and an important alternative for biofuel production. The fast pyrolysis of biomass is an economical and advantageous to get bio-oil. However, bio-oil has a large amount of oxygenated compounds and needs upgrade. The catalytic process of HDO （hydrodeoxygenation） is the most efficient way to remove oxygen from the bio-oil. In this paper, it was studied the HDO phenol （300 ℃ and 35 atm） on catalysts based on cobalt or copper oxides supported on HBeta zeolite. The catalysts were characterized by XRD （X-ray diffraction）, FTIR （infrared spectroscopy） and NH3-TPD （desorption of ammonia）. The results showed the presence of CO304 （cobalt oxide） and CuO （copper oxide）. The measurements showed the presence of acid sites weak, moderate and strong and that the impregnation of the metal oxide modifying the acidity of the support. The results showed the following order HDO conversion： CoHBeta 〉 CuHBeta 〉 HBeta. The presence of the cobalt or copper catalysts contributes to the increase in conversion due to hydrogenation. All catalysts were selective to benzene, but only the impregnated catalysts showed selectivity to cyclohexane and cyclohexene.展开更多
Deactivation of Pd/C catalyst often occurs in liquid hydrogenation using industrial materials. For in-stance, the Pd/C catalyst is deactivated severely in the hydrogenation of N-(3-nitro-4-methoxyphenyl) acetamide. In...Deactivation of Pd/C catalyst often occurs in liquid hydrogenation using industrial materials. For in-stance, the Pd/C catalyst is deactivated severely in the hydrogenation of N-(3-nitro-4-methoxyphenyl) acetamide. In this study, the chemisorption of sulfur on the surface of deactivated Pd/C was detected by energy dispersive spec-trometer and X-ray photoelectron spectroscopy. Sulfur compounds poison the Pd/C catalyst and increase the forma-tion of azo deposit, reducing the activity of catalyst. We report a mild method to regenerate the Pd/C catalyst: wash the deposit by N,N-dimethylformamide and oxidize the chemisorbed sulfur by hot air. The regenerated Pd/C cata-lyst can be reused at least ten runs with stable activity.展开更多
Mesoporous CeO2 nanowires(NWs) were synthesized through a facile hydrothermal process by using triblock copolymer F127 as the template.XRD analysis confirmed the cubic phase of the synthesized CeO2 NWs.High-yield one-...Mesoporous CeO2 nanowires(NWs) were synthesized through a facile hydrothermal process by using triblock copolymer F127 as the template.XRD analysis confirmed the cubic phase of the synthesized CeO2 NWs.High-yield one-dimensional NWs with accessible mesopores could be observed from SEM and TEM images,and the surface area of the material was confirmed to be 273 m2 g-1 with pore width distribution of 6.9-13.8 nm.The mesoporous CeO2 NWs could be used as efficient photocatalysts for organic dye degradation under UV light irradiation,which was superior compared with commercial photocatalyst P-25 and commercial CeO2 powders.The NW structure facilitates the recovery of catalyst by sedimentation,leading to the impressive reusability of these mesoporous CeO2 NWs.展开更多
文摘In industrial catalytic processes,coke deposition can cause catalyst deactivation by covering acid sites and/or blocking pores.The regeneration of deactivated catalysts,thereby removing the coke and simultaneously restoring the catalytic activity,is highly desired.Despite various chemical reactions and methods are available to remove coke,developing reliable,efficient,and economic regeneration methods for catalytic processes still remains a challenge in industrial practice.In this paper,the current progress of regeneration methods such as oxidation(air,ozone and oxynitride),gasification(carbon dioxide and water steam),and hydrogenation(hydrogen)is reviewed,which hopefully can shed some light on the design and optimization of catalysts and the related processes.
文摘Biomass is considered the largest renewable energy source and an important alternative for biofuel production. The fast pyrolysis of biomass is an economical and advantageous to get bio-oil. However, bio-oil has a large amount of oxygenated compounds and needs upgrade. The catalytic process of HDO （hydrodeoxygenation） is the most efficient way to remove oxygen from the bio-oil. In this paper, it was studied the HDO phenol （300 ℃ and 35 atm） on catalysts based on cobalt or copper oxides supported on HBeta zeolite. The catalysts were characterized by XRD （X-ray diffraction）, FTIR （infrared spectroscopy） and NH3-TPD （desorption of ammonia）. The results showed the presence of CO304 （cobalt oxide） and CuO （copper oxide）. The measurements showed the presence of acid sites weak, moderate and strong and that the impregnation of the metal oxide modifying the acidity of the support. The results showed the following order HDO conversion： CoHBeta 〉 CuHBeta 〉 HBeta. The presence of the cobalt or copper catalysts contributes to the increase in conversion due to hydrogenation. All catalysts were selective to benzene, but only the impregnated catalysts showed selectivity to cyclohexane and cyclohexene.
基金Supported by the Natural Science Foundation of Zhejiang Provincial （LYI2B03009） and Program for Zhejiang Leading Team of Science and Technology Innovation （2011 R09020-03）.
文摘Deactivation of Pd/C catalyst often occurs in liquid hydrogenation using industrial materials. For in-stance, the Pd/C catalyst is deactivated severely in the hydrogenation of N-(3-nitro-4-methoxyphenyl) acetamide. In this study, the chemisorption of sulfur on the surface of deactivated Pd/C was detected by energy dispersive spec-trometer and X-ray photoelectron spectroscopy. Sulfur compounds poison the Pd/C catalyst and increase the forma-tion of azo deposit, reducing the activity of catalyst. We report a mild method to regenerate the Pd/C catalyst: wash the deposit by N,N-dimethylformamide and oxidize the chemisorbed sulfur by hot air. The regenerated Pd/C cata-lyst can be reused at least ten runs with stable activity.
基金supported by the Engineering and Technology Research Center of Food Preservation,Processing and Safety Control of Liaoning Province,Food Safety Key Lab of Liaoning Province (LNSAKF2011027)Key Laboratory Project of Department of Education of LiaoningProvince (2009s004)
文摘Mesoporous CeO2 nanowires(NWs) were synthesized through a facile hydrothermal process by using triblock copolymer F127 as the template.XRD analysis confirmed the cubic phase of the synthesized CeO2 NWs.High-yield one-dimensional NWs with accessible mesopores could be observed from SEM and TEM images,and the surface area of the material was confirmed to be 273 m2 g-1 with pore width distribution of 6.9-13.8 nm.The mesoporous CeO2 NWs could be used as efficient photocatalysts for organic dye degradation under UV light irradiation,which was superior compared with commercial photocatalyst P-25 and commercial CeO2 powders.The NW structure facilitates the recovery of catalyst by sedimentation,leading to the impressive reusability of these mesoporous CeO2 NWs.
