A Ni-La/SiO2 catalyst was prepared through the incipient wetness impregnation method and tested in the oxidative dehydrogenation of ethane （ODHE） with CO2. The fresh and used catalysts were characterized by XRD and ...A Ni-La/SiO2 catalyst was prepared through the incipient wetness impregnation method and tested in the oxidative dehydrogenation of ethane （ODHE） with CO2. The fresh and used catalysts were characterized by XRD and SEM techniques. The Ni-La/SiO2 catalyst exhibited catalytic activity for the oxidative dehydrogenation of ethane, but with low ethylene selectivity in the absence of methane. The selectivity to ethylene increased with increasing molar ratio of methane in the feed. The carbon deposited on the catalyst surface in the sole ODHE with CO2 was mainly inert carbon, while much more filamentous carbon was formed in the presence of methane. The filamentous carbon was easy to be removed by CO2, which might play a role in improving the conversion of ethane to ethylene. The introduction of methane might affect the equilibrium of the CO2 reforming of ethane and the ODHE with CO2. As a consequence, the synthesis gas produced from CO2 reforming of methane partly inhibited the reaction of ethane and promoted the ODHE with CO2, thus increasing the selectivity of ethylene.展开更多
以V_2O_5为活性组分,通过对催化剂活性组分、载体结构和助剂等因素的研究,制备La-V/TiO_2-SiO_2催化剂,在n(甲醇)∶n(乙醇)=4∶1、空速1.5 h-1、氮气流量120 m L·min^(-1)、反应温度360℃和常压条件下,乙醇转化率84%,异丁醛选择性...以V_2O_5为活性组分,通过对催化剂活性组分、载体结构和助剂等因素的研究,制备La-V/TiO_2-SiO_2催化剂,在n(甲醇)∶n(乙醇)=4∶1、空速1.5 h-1、氮气流量120 m L·min^(-1)、反应温度360℃和常压条件下,乙醇转化率84%,异丁醛选择性67%。展开更多
M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the specie...M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the species have hexagonal crystal structure and no diffraction peaks of SiO2 are found. The structure of BaLaxFe12-xO19 seems uniform at different La doping dosage. Fourier transform infrared (FTIR) proves the co-existence of SiO2 and ferrites in the produc-ts. The addition of SiO2 nanoparticles promotes the formation of more homogeneous and finer ferrite crystal, as proved by scanning electron microscopy (SEM). Compared with BaLa0.5Fe11.5O19 powders synthesized without SiO2 nanoparticles, those synthesized in the presence of SiO2 nanoparticles present in smaller powder size and similar structure.展开更多
采用浸渍法制备出γ-Al2O3、SiO2和γ-Al2O3.SiO2负载的Ni-La催化剂,用XRD、TPR、XPS、H2-TPD、NH3-TPD和TG等手段对催化剂进行了表征,结果表明:这3种负载型催化剂中的活性组分Ni的分散度较高,La3+氧化物高度分散于载体表面.在温度为40...采用浸渍法制备出γ-Al2O3、SiO2和γ-Al2O3.SiO2负载的Ni-La催化剂,用XRD、TPR、XPS、H2-TPD、NH3-TPD和TG等手段对催化剂进行了表征,结果表明:这3种负载型催化剂中的活性组分Ni的分散度较高,La3+氧化物高度分散于载体表面.在温度为400℃、水醇比为4.0和液体空速为8.0 mL h-1gc-at1的条件下,催化剂进行稳定性测试,结果表明:γ-Al2O3.SiO2负载的Ni-La催化剂在整个100 h稳定性测试过程中,氢气的选择性保持在67.0%左右,且稳定性良好.对经过稳定性测试后的Ni-La催化剂进行热重分析,发现γ-Al2O3.SiO2负载的Ni-La催化剂具有较少的积碳量,仅仅是0.86 g C.gc-at1,其中石墨碳占42.81%.展开更多
基金supported by the NNSFC (Nos. 20976109, 21021001)the Special Research Foundation of Doctoral Education of China (No.20090181110046)
文摘A Ni-La/SiO2 catalyst was prepared through the incipient wetness impregnation method and tested in the oxidative dehydrogenation of ethane （ODHE） with CO2. The fresh and used catalysts were characterized by XRD and SEM techniques. The Ni-La/SiO2 catalyst exhibited catalytic activity for the oxidative dehydrogenation of ethane, but with low ethylene selectivity in the absence of methane. The selectivity to ethylene increased with increasing molar ratio of methane in the feed. The carbon deposited on the catalyst surface in the sole ODHE with CO2 was mainly inert carbon, while much more filamentous carbon was formed in the presence of methane. The filamentous carbon was easy to be removed by CO2, which might play a role in improving the conversion of ethane to ethylene. The introduction of methane might affect the equilibrium of the CO2 reforming of ethane and the ODHE with CO2. As a consequence, the synthesis gas produced from CO2 reforming of methane partly inhibited the reaction of ethane and promoted the ODHE with CO2, thus increasing the selectivity of ethylene.
基金Project supported by Fund for Harbin Young Scholars (2005AFQ X J 0 31)
文摘M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the species have hexagonal crystal structure and no diffraction peaks of SiO2 are found. The structure of BaLaxFe12-xO19 seems uniform at different La doping dosage. Fourier transform infrared (FTIR) proves the co-existence of SiO2 and ferrites in the produc-ts. The addition of SiO2 nanoparticles promotes the formation of more homogeneous and finer ferrite crystal, as proved by scanning electron microscopy (SEM). Compared with BaLa0.5Fe11.5O19 powders synthesized without SiO2 nanoparticles, those synthesized in the presence of SiO2 nanoparticles present in smaller powder size and similar structure.
文摘采用浸渍法制备出γ-Al2O3、SiO2和γ-Al2O3.SiO2负载的Ni-La催化剂,用XRD、TPR、XPS、H2-TPD、NH3-TPD和TG等手段对催化剂进行了表征,结果表明:这3种负载型催化剂中的活性组分Ni的分散度较高,La3+氧化物高度分散于载体表面.在温度为400℃、水醇比为4.0和液体空速为8.0 mL h-1gc-at1的条件下,催化剂进行稳定性测试,结果表明:γ-Al2O3.SiO2负载的Ni-La催化剂在整个100 h稳定性测试过程中,氢气的选择性保持在67.0%左右,且稳定性良好.对经过稳定性测试后的Ni-La催化剂进行热重分析,发现γ-Al2O3.SiO2负载的Ni-La催化剂具有较少的积碳量,仅仅是0.86 g C.gc-at1,其中石墨碳占42.81%.
