A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-...A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-ray diffraction （XRD）,BET,temperature-programmed desorption of ammonia （NH3-TPD）,temperature-programmed reduction of hydrogen （H2-TPR） and H2-chemisorption techniques,and evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor.The reaction temperature,time on stream,space velocity,and the ratio of H2/n-heptane are changed to get the optimal conditions.The Ce（III） and La（III）-exchanged Hβ-zeolites exhibit higher selectivity for isomerized products than the neat Hβ-zeolite.Moreover,the Ce（III）-exchanged catalysts give higher conversions of n-heptane,whereas the La（III）-exchanged ones do not show any improvement in con-version.Under optimal conditions,the catalyst with 0.4% （by mass） Pt and 0.5% （by mass） Ce loading presents very high selectivity of isomerized products of 95.1% coupled with high n-heptane conversion of 68.7%.Effects of the ion-exchange of Ce（III） and La（III） on the catalytic performance are discussed in relation with the physico-chemical properties of catalysts.展开更多
The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by...The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by BET, XRD (X-ray diffraction), TPR (temperature programmed reduction), IR (infra-red adsorption), NH 3-TPD (temperature programmed desorption) and CO 2-TPD (temperature programmed desorption) techniques. The results showed that the surface area of catalysts decreased with increasing metal content, and the metals as well as Cu-Ni alloy co-existed on the reduced catalyst surface. There existed interaction between metal and carrier, and moreover, metal particles affected obviously the acidity and basicity of carrier. The large amount of basic sites facilitated the activation of methanol to methoxyl species and their subsequent reaction with activated carbon dioxide. The catalysts were evaluated in a continuous tubular fixed-bed micro-gaseous reactor and the catalyst with bimetal loading of 20% (by mass) had best catalytic activities. Under the conditions of 393 K, 1.1 MPa, 5 h and gas space velocity of 510 h 1 , the selectivity and yield of DMC were higher than 86.0 % and 5.0 %, respectively.展开更多
FT-IR spectrometry, TPD and adsorption isotherms of thiophene on NaY/NiY zeolites were carried out and the diffusion coefficient was obtained by means of its real-time dynamic curves. The loading of thiophene adsorbed...FT-IR spectrometry, TPD and adsorption isotherms of thiophene on NaY/NiY zeolites were carried out and the diffusion coefficient was obtained by means of its real-time dynamic curves. The loading of thiophene adsorbed on the NaY zeolite decreased with an increasing temperature, which was ascribed to the patterns of physical adsorption. Both physical and chemical adsorption phenomena were detected on the NiY zeolite, with the 0 complexation and S-M interaction existing during the chemical adsorption. The loading of thiophene adsorbed on the NiY zeolite at 302 K and 335 K was equal, but it decreased at 373 K. The diffusion coefficient of thiophene on the NaY zeolite decreased when the loading increased to more than 0.02 mmol/g, and on the contrary that of thiophene on the NiY zeolite did not change obviously with the loading adsorbed.展开更多
基金Supported by the Jiangsu Provincial Key Natural Science Foundation for Universities（06KJA53012） the National Natural Science Foundation of China（20476046 20976084）
文摘A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-ray diffraction （XRD）,BET,temperature-programmed desorption of ammonia （NH3-TPD）,temperature-programmed reduction of hydrogen （H2-TPR） and H2-chemisorption techniques,and evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor.The reaction temperature,time on stream,space velocity,and the ratio of H2/n-heptane are changed to get the optimal conditions.The Ce（III） and La（III）-exchanged Hβ-zeolites exhibit higher selectivity for isomerized products than the neat Hβ-zeolite.Moreover,the Ce（III）-exchanged catalysts give higher conversions of n-heptane,whereas the La（III）-exchanged ones do not show any improvement in con-version.Under optimal conditions,the catalyst with 0.4% （by mass） Pt and 0.5% （by mass） Ce loading presents very high selectivity of isomerized products of 95.1% coupled with high n-heptane conversion of 68.7%.Effects of the ion-exchange of Ce（III） and La（III） on the catalytic performance are discussed in relation with the physico-chemical properties of catalysts.
基金Supported by the National High Technology Research and Development Program of China (2008AA03Z3472294,2009AA302410)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2010)+1 种基金the Guangdong Province Sci & Tech Bureau (2006B12401006, 2008A080800024)the Chinese Universities Basic Research Founding
文摘The 0.4 nm molecular sieve supported Cu-Ni bimetal catalysts for direct synthesis of dimethyl carbonate (DMC) from CO 2 and CH 3 OH were prepared and investigated. The synthesized catalysts were fully characterized by BET, XRD (X-ray diffraction), TPR (temperature programmed reduction), IR (infra-red adsorption), NH 3-TPD (temperature programmed desorption) and CO 2-TPD (temperature programmed desorption) techniques. The results showed that the surface area of catalysts decreased with increasing metal content, and the metals as well as Cu-Ni alloy co-existed on the reduced catalyst surface. There existed interaction between metal and carrier, and moreover, metal particles affected obviously the acidity and basicity of carrier. The large amount of basic sites facilitated the activation of methanol to methoxyl species and their subsequent reaction with activated carbon dioxide. The catalysts were evaluated in a continuous tubular fixed-bed micro-gaseous reactor and the catalyst with bimetal loading of 20% (by mass) had best catalytic activities. Under the conditions of 393 K, 1.1 MPa, 5 h and gas space velocity of 510 h 1 , the selectivity and yield of DMC were higher than 86.0 % and 5.0 %, respectively.
文摘FT-IR spectrometry, TPD and adsorption isotherms of thiophene on NaY/NiY zeolites were carried out and the diffusion coefficient was obtained by means of its real-time dynamic curves. The loading of thiophene adsorbed on the NaY zeolite decreased with an increasing temperature, which was ascribed to the patterns of physical adsorption. Both physical and chemical adsorption phenomena were detected on the NiY zeolite, with the 0 complexation and S-M interaction existing during the chemical adsorption. The loading of thiophene adsorbed on the NiY zeolite at 302 K and 335 K was equal, but it decreased at 373 K. The diffusion coefficient of thiophene on the NaY zeolite decreased when the loading increased to more than 0.02 mmol/g, and on the contrary that of thiophene on the NiY zeolite did not change obviously with the loading adsorbed.
