A novel Pd/Al 2O 3 catalyst prepared by glow discharge plasma technology is reported.The results of H 2-chemisorption indicate that palladium dispersion of the plasma-prepared Pd/Al 2O 3 reaches 29.7%,which is about 5...A novel Pd/Al 2O 3 catalyst prepared by glow discharge plasma technology is reported.The results of H 2-chemisorption indicate that palladium dispersion of the plasma-prepared Pd/Al 2O 3 reaches 29.7%,which is about 5 times higher than Pd/Al 2O 3 prepared by conventional preparation.Meanwhile,the particle diameter of the plasma-prepared catalyst is 3.8 nm, but the particle diameter of the conventional catalyst is 20.4 nm.Such plasma-prepared Pd/Al 2O 3 catalyst shows a higher activity for catalytic combustion of methane than the conventional catalyst.Methane conversion reaches 90% at 400 ℃, but it is only near 30% for the conventional catalyst at the same temperature.展开更多
A series of Ni,Sn and Ca modified Pd/TiO2-Al2O3catalysts were prepared by the incipient wetness impregnation method and their catalytic performance for the selective catalytic reduction of NOxby H2was evaluated.The re...A series of Ni,Sn and Ca modified Pd/TiO2-Al2O3catalysts were prepared by the incipient wetness impregnation method and their catalytic performance for the selective catalytic reduction of NOxby H2was evaluated.The results showed that the NOxconversion and N2selectivity were improved over Pd-Sn/TiO2-Al2O3and Pd-Ni/TiO2-Al2O3catalysts above 200°C.More importantly,the N2selectivity and high-temperature activity of Pd-Sn/TiO2-Al2O3catalyst was far superior to the single Pd/TiO2-Al2O3catalyst.The optimal Sn loading was 2 wt.%.X-ray diffraction(XRD)results showed that the interaction between Pd and Sn promotes the dispersion of Pd over TiO2-Al2O3.Temperature-programmed reduction(H2-TPR)results demonstrated that the addition of Sn contributes to the formation of Pd0and improving the redox property of Pd/TiO2-Al2O3.The additives of Ni and Sn also facilitated the absorption of NOxand the oxidation of NO to NO2,which play important roles in the selective catalytic reduction of NOxby hydrogen.展开更多
A Pd-Ag （24 wt%） alloy composite membrane was prepared by the magnetron sputtering. A γ-Al<sub>2</sub>O<sub>3</sub> membrane was synthesized by the sol-gel method and used as substrate of th...A Pd-Ag （24 wt%） alloy composite membrane was prepared by the magnetron sputtering. A γ-Al<sub>2</sub>O<sub>3</sub> membrane was synthesized by the sol-gel method and used as substrate of the Pd-Ag alloy film. The process parameters of the magnetron sputtering were optimized as a function of the compactness of the Pd-Ag alloy film. The best membrane with a thickness of 1 μm was produced with a sputtering pressure of 2.7 Pa and a substrate temperature of 400℃. The membrane had an H<sub>2</sub>/N<sub>2</sub> permselectivity of 51.5--1000 and an H<sub>2</sub> permeation rate of 0.036--1.17×10<sup>-5</sup>cm<sup>3</sup>/cm<sup>2</sup>·s· Pa, depending on operating conditions.展开更多
文摘A novel Pd/Al 2O 3 catalyst prepared by glow discharge plasma technology is reported.The results of H 2-chemisorption indicate that palladium dispersion of the plasma-prepared Pd/Al 2O 3 reaches 29.7%,which is about 5 times higher than Pd/Al 2O 3 prepared by conventional preparation.Meanwhile,the particle diameter of the plasma-prepared catalyst is 3.8 nm, but the particle diameter of the conventional catalyst is 20.4 nm.Such plasma-prepared Pd/Al 2O 3 catalyst shows a higher activity for catalytic combustion of methane than the conventional catalyst.Methane conversion reaches 90% at 400 ℃, but it is only near 30% for the conventional catalyst at the same temperature.
基金supported by the National Natural Science Foundation of China (21377010)the Fundamental Research Funds for the Central Universities (YS1401)the Program for New Century Excellent Talents in University,Ministry of Education,China (NCET-13-0650)
文摘A series of Ni,Sn and Ca modified Pd/TiO2-Al2O3catalysts were prepared by the incipient wetness impregnation method and their catalytic performance for the selective catalytic reduction of NOxby H2was evaluated.The results showed that the NOxconversion and N2selectivity were improved over Pd-Sn/TiO2-Al2O3and Pd-Ni/TiO2-Al2O3catalysts above 200°C.More importantly,the N2selectivity and high-temperature activity of Pd-Sn/TiO2-Al2O3catalyst was far superior to the single Pd/TiO2-Al2O3catalyst.The optimal Sn loading was 2 wt.%.X-ray diffraction(XRD)results showed that the interaction between Pd and Sn promotes the dispersion of Pd over TiO2-Al2O3.Temperature-programmed reduction(H2-TPR)results demonstrated that the addition of Sn contributes to the formation of Pd0and improving the redox property of Pd/TiO2-Al2O3.The additives of Ni and Sn also facilitated the absorption of NOxand the oxidation of NO to NO2,which play important roles in the selective catalytic reduction of NOxby hydrogen.
基金Project supported by the National Natural Science Foundation of China (Grant No. 29392003)the Chinese Academy of Sciences (Grant No. KMX 85-23), German BMBF and FhG-IGB.
文摘A Pd-Ag （24 wt%） alloy composite membrane was prepared by the magnetron sputtering. A γ-Al<sub>2</sub>O<sub>3</sub> membrane was synthesized by the sol-gel method and used as substrate of the Pd-Ag alloy film. The process parameters of the magnetron sputtering were optimized as a function of the compactness of the Pd-Ag alloy film. The best membrane with a thickness of 1 μm was produced with a sputtering pressure of 2.7 Pa and a substrate temperature of 400℃. The membrane had an H<sub>2</sub>/N<sub>2</sub> permselectivity of 51.5--1000 and an H<sub>2</sub> permeation rate of 0.036--1.17×10<sup>-5</sup>cm<sup>3</sup>/cm<sup>2</sup>·s· Pa, depending on operating conditions.
