Pd supported on TiO2-Al2O3 binary oxides prepared by coprecipitation method has been investigated for the total oxidation of methane. All Pd/TiO2-Al2O3 catalysts show higher activity than Pd/Al2O3 and Pd/TiO2. Among t...Pd supported on TiO2-Al2O3 binary oxides prepared by coprecipitation method has been investigated for the total oxidation of methane. All Pd/TiO2-Al2O3 catalysts show higher activity than Pd/Al2O3 and Pd/TiO2. Among them, Pd/2Ti-3Al with a Ti/Al ratio of 2 to 3 has a T90% of 395 ℃ at a gas hourly mass velocity of 33000 mL/（h＊g）, which is at least 50 ℃ lower than that of Pd supported on single metal oxide Al2O3 or TiO2. The results of TPR and ^180-isotope exchange experiments demonstrated that the excellent activity of Pd/2Ti-3Al was due to its high oxygen mobility and moderate reducibility, which is in accordance with our previous work, XPS results indicated that the dispersion of Pd was not the key factor to influence the catalytic activity.展开更多
Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption,...Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.展开更多
In this work, Pd–Cu/γ-Al2O3 is prepared by the impregnation method and investigated for selective oxygenization of cyclopentene to cyclopentanone. A series of bimetallic Pd–Cu/γ-Al_(2)O_(3) nanocatalysts were prep...In this work, Pd–Cu/γ-Al2O3 is prepared by the impregnation method and investigated for selective oxygenization of cyclopentene to cyclopentanone. A series of bimetallic Pd–Cu/γ-Al_(2)O_(3) nanocatalysts were prepared and the structures characterized by XRD, XPS and TEM. We determined that the obtained Pd–Cu/γ-Al_(2)O_(3)(molar ratio Pd:Cu = 5:1) was an efficient catalyst for the oxygenization of cyclopentene to cyclopentanone with 95% selectivity and 85% conversion(100 °C, 1 MPa initial O2 pressure, 7 h).展开更多
A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The struct...A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.展开更多
基金Project supported by the Major State Basic Research Development Program （No. G2000077503）, the National Natural Science Foundation of China （No. 20173002）, and Cooperation Project between NSFC and DFG （No. 20411130104）.
文摘Pd supported on TiO2-Al2O3 binary oxides prepared by coprecipitation method has been investigated for the total oxidation of methane. All Pd/TiO2-Al2O3 catalysts show higher activity than Pd/Al2O3 and Pd/TiO2. Among them, Pd/2Ti-3Al with a Ti/Al ratio of 2 to 3 has a T90% of 395 ℃ at a gas hourly mass velocity of 33000 mL/（h＊g）, which is at least 50 ℃ lower than that of Pd supported on single metal oxide Al2O3 or TiO2. The results of TPR and ^180-isotope exchange experiments demonstrated that the excellent activity of Pd/2Ti-3Al was due to its high oxygen mobility and moderate reducibility, which is in accordance with our previous work, XPS results indicated that the dispersion of Pd was not the key factor to influence the catalytic activity.
基金Project supported by National Natural Science Foundation of China (20773090, 20803049)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026, 200806100009)
文摘Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.
基金financial assistance from the National Natural Science Foundation of China (Nos. 21272050, 21371044, 21472033 and 21571047)
文摘In this work, Pd–Cu/γ-Al2O3 is prepared by the impregnation method and investigated for selective oxygenization of cyclopentene to cyclopentanone. A series of bimetallic Pd–Cu/γ-Al_(2)O_(3) nanocatalysts were prepared and the structures characterized by XRD, XPS and TEM. We determined that the obtained Pd–Cu/γ-Al_(2)O_(3)(molar ratio Pd:Cu = 5:1) was an efficient catalyst for the oxygenization of cyclopentene to cyclopentanone with 95% selectivity and 85% conversion(100 °C, 1 MPa initial O2 pressure, 7 h).
基金supported by the National Natural Science Foundation of China(21377018)the Natural Science Foundation of Liaoning Province of China(2013020116)the Fundamental Research Funds for the Central Universities(DUT15ZD240)~~
文摘A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.
基金supported by the National Natural Science Foundation of China(21173153)National Hi-tech Research and Development Program of China(863)(2015AA034603)Opening Project of Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education,China(LYJ1407)~~
