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P. Da Costa C. Potvin J.-M. Manoli M. Breysse G. Djega-Mariadassou 《Catalysis Letters》2003,86(1-3):133-138
Hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene on alumina-supported Mo2C has been studied. These catalysts are stable and active under deep HDS conditions (0-250 wt ppm S). However, although they are well known to have hydrogenation properties, they lead preferentially to a non-hydrogenated product of the HDS reaction: dimethylbiphenyl. For the same reaction, supported platinum and sulfided molybdenum oxide lead to the hydrogenated products dimethyldicyclohexyl and methylcyclohexyltoluene, respectively. The ranking of HDS activity is as follows: MoS2/Al2O3 < Mo2C/Al2O3 < Pt/SiO2. 相似文献
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996.
Carbon nanofibers (CNFs) have been synthesized by co-catalyst deoxidization process by a reaction between C2H5OC2H5, Zn and Fe powder at 650 °C for 10 h. These nanofibers exhibit diameters of ∼80 nm and lengths ranging from several micrometers to tens of micrometers. X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy indicate that as-prepared CNFs possess low graphitic crystallinity. The resultant CNFs as electrode shows capacity of ∼220 mAh/g and high reversibility with little hysteresis in the insertion/deintercalation reactions of lithium-ion. In addition, the possible growth of CNFs is discussed. 相似文献
997.
The role of Ag in simultaneously catalyzing NO reduction and C3H6 oxidation was shown to be strongly dependent on the redox properties of its local environment. Under an atmosphere of 1,000 ppm
NO, 3,000 ppm C3H6, and 1% O2 and a GHSV of 30,000 h−1, a perovskite La0.88Ag0.12FeO3 prepared by reactive grinding is active giving a complete NO conversion and 92% C3H6 conversion at 500 °C. These values are much higher than the NO conversion of 55% and C3H6 conversion of 45% obtained over a 3 wt.% Ag/Al2O3 catalyst under the same conditions. Under an excess of oxygen (10% O2) a good SCR performance with a plateau of N2 yield above 97% over a wide temperature window of 350–500 °C along with C3H6 conversion of 90% at 500 °C was observed over Ag/Al2O3, while minor N2 yields (∼10% at 250–350 °C) and high C3H6 conversions (reaching ∼100% at 450 °C) were obtained over La0.88Ag0.12FeO3. Abundant molecular oxygen is desorbed from Ag substituted perovskite after 10% O2 adsorption as verified by O2- temperature programmed desorption (TPD). This reflects the strongly oxidative properties of La0.88Ag0.12FeO3, which lead to a satisfactory NO reduction at 1% O2 due to the ease of nitrate formation but to a significant C3H6 combustion above that value. The formation of nitrate species over the less oxidizing Ag/Al2O3 was accelerated under an excess of oxygen resulting in an excellent lean NO reduction behavior. The redox properties of silver
catalysts could be adjusted via mixing perovskite with alumina for an optimal elimination of both NO and C3H6 over the whole range of oxygen concentration between 0 to 10%. 相似文献
998.
稀土复合热稳定剂对聚氯乙烯性能影响研究 总被引:7,自引:0,他引:7
主要以有机锡热稳定剂为对比物,研究了稀土热稳定剂对聚氯乙烯(PVC)的热稳定性及其他性能的影响。稀土热稳定剂对PVC的力学性能、加工性能都有不同程度的提高,稀土热稳定剂的热稳定性能符合PVC的加工条件要求,并研究了抗冲改性剂ACR(丙烯酸酯共聚物)对体系的影响。 相似文献
999.
1000.