Catalytic methanation of syngas over Ni-based catalysts with different supports

Co-precipitation method was selected for the preparation of Ni/Al_2O_3, Ni/ZrO_2 and Ni/CeO_2 catalysts, and their performances in methanation were investigated in this study. The structure and surface properties of these catalysts were characterized by BET, XRD, H_2-TPD, TEM and H_2-TPR. The results showed that the catalytic activity at low temperature followed the order: Ni/Al_2O_3>Ni/ZrO_2>Ni/CeO_2. Ni/Al_2O_3 catalyst presented the best catalytic performance with the highest CH_4 selectivity of 94.5%. The characterization results indicated that the dispersion of the active component Ni was the main factor affecting the catalytic activity and the one with higher dispersion gave better performance.

SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES^(**)

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.

Pt/FeSnO(OH)_5： A Novel Supported Pt Catalyst for Catalytic Oxidation of Benzene

Pt/FeSnO（OH）_5 was synthesized as a novel catalyst for VOCs oxidation. Compared with Pt/γ-Al_2O_3 during catalytic oxidation of benzene, Pt/Fe Sn O（OH）5 showed better catalytic activity. After characterization of the catalysts by XRD, SEM, TEM, EDS, XPS, BET, TGA and DTA, we found most Pt could be reduced to metallic state when the hydroxyl catalyst was used as supporter, and the metallic Pt in Pt/Fe Sn O（OH）5 was more active than the oxidized Pt in Pt/γ-Al_2O_3 in catalytic oxidation of VOCs. Pt/FeSnO（OH）_5 shows both good catalytic activity and high stability, which may be a promising catalyst. This study may also be helpful for the design and fabrication of new catalysts.

Effects of support property on the catalytic performance of CeO_2-ZrO_2-CrO_x for 1,2-dichloroethane oxidation

HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane（DCE）, as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N_2 adsorption-desorption, X-ray photoelectron spectroscopy（XPS）, ammonia-temperatureprogrammed desorption（NH_3-TPD） and hydrogen temperature-programmed reduction（H2-TPR）. The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20% CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order： 20%CZCr/HZSM-5〉CZCr〉20%CZCr/TiO_2〉20%CZCr/Al_2O_3〉20%CZCr/SiO_2.

Plasma-assisted Co/Zr-metal organic framework catalysis of CO_(2)hydrogenation:influence of Co precursors

In this study,Co/Zr-metal organic framework(MOF)precursors were obtained by a roomtemperature liquid-phase precipitation method and the equivalent-volume impregnation method,respectively,using a Zr-MOF as the support,and Co/Zr-MOF-M and Co/Zr-MOF-N catalysts were prepared after calcination in a hydrogen-argon mixture gases(VAr:V_(H_(2))=9:1)at 350℃for 2 h.The catalytic activities of the prepared samples for CO_(2)methanation under atmosphericpressure cold plasma were studied.The results showed that Co/Zr-MOF-M had a good synergistic effect with cold plasma.At a discharge power of 13.0 W,V_(H_(2)):VCO_(2)=4:1 and a gas flow rate of 30 ml·min^(-1),the CO_(2)conversion was 58.9%and the CH4 selectivity reached 94.7%,which was higher than for Co/Zr-MOF-N under plasma(CO_(2)conversion 24.8%,CH4 selectivity 9.8%).X-ray diffraction,scanning electron microscopy,transmission electron microscopy,N_(2)adsorption and desorption(Brunauer-Emmett-Teller)and x-ray photoelectron spectroscopy analysis results showed that Co/Zr-MOF-M and Co/Zr-MOF-N retained a good Zr-MOF framework structure,and the Co oxide was uniformly dispersed on the surface of the Zr-MOF.Compared with Co/Zr-MOF-N,the Co/Zr-MOF-M catalyst has a larger specific surface area and higher Co^(2+)/Cototaland Co/Zr ratios.Additionally,the Co oxide in Co/ZrMOF-M is distributed on the surface of the Zr-MOF in the form of porous particles,which may be the main reason why the catalytic activity of Co/Zr-MOF-M is higher than that of Co/ZrMOF-N.