Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior...Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior of these two oxides with the perovskite structure was studied during the reaction of methane oxidation. The pre\|treatment with methane has different effect on the catalytic activities of both the oxides. The methane pre\|treatment has not resulted in the change of the catalytic activity of BSCFO owing to its excellent reversibility of the perovskite structure resulting from the excellent synergistic interaction between Co and Fe in the oxide. However, the substitution with Ti on Fe\|site in the lattice makes the methane pre\|treatment have an obvious influence on the activity of the formed BSCTO oxide.展开更多
TiO2-Al2O3 binary okides were prepared by gas-phase deposition of TiCly on r-Al2os support. It was found that TiO2 deposition is formd by the reaction of TiCl4 vapour with OH- group on A12O3 stirface. The TiO2 loading...TiO2-Al2O3 binary okides were prepared by gas-phase deposition of TiCly on r-Al2os support. It was found that TiO2 deposition is formd by the reaction of TiCl4 vapour with OH- group on A12O3 stirface. The TiO2 loading increases with the number of gas phase deposition operations and the tetrahedral sites of Al2O3 surface was first covered by TiO2. S1ightly decrease of surface area) pore value and average of pore diameter of TiOz-AlzO3 compared with Al2O3 was observed. In Mo/TiO2-Al2O3 catalysts Mo ealsts maally in the form of octalledla and polymer Mo7O2’ species, while no tetrahedral Mo species has been observed. The model of Mo/TiO2-Al2O3 catalyst could be imagined as a sandwich of MoO2-TiO2-Al2O3. Due to the weaker interaction between Mo species and A1zoa support in this case more Mo6+ ions in Mo/TiO2-Al2O3 sample are reduced to low valence state comparing with that of Mo/Al2O3 at 5o(f C in H2. The experimental results demonstrate that the HDS and HYD activities of Mo/TiO2-Al2O3 catalysts increase with Tioz content. It means that the full coverage of Al2o3 surface by TiO2 can driprove effectively the catalyst activity of molybdenum catalyst in hydrotreating process.展开更多
XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Mo...XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Moδ+:δ■4) when reduc tion temperature was raised up to 673K, meanwhile sharp increases of both the irreversible and reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent. Accordingly, the active sites towards hydrogen adsorption are tentatively proposed to the low valence molybdenum species with nitrogen deficient.展开更多
Carbon nanotube is found to be a novel support for the selective hydrogenation of citral in this paper. Selective hydrogenation of citral was carried out in an autoclave at 5 MPa and 323 K. The results indicate that t...Carbon nanotube is found to be a novel support for the selective hydrogenation of citral in this paper. Selective hydrogenation of citral was carried out in an autoclave at 5 MPa and 323 K. The results indicate that the selectivity of the products, unsaturated alcohols, is about 86 over Pt/CNTs catalyst and 48 over Pt/XC-72 catalyst, respectively. The differential heat of CO adsorption measured by microcalorimetry is firstly used to probe surface adsorption sites of platinum catalyst supported on carbon nanotubes. The experimental results indicate that the Pt/CNTs catalyst shows a higher initial differential heat of CO adsorption(126 kJ/mol) than the Pt/XC-72 catalyst(106 kJ/mol).展开更多
文摘Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior of these two oxides with the perovskite structure was studied during the reaction of methane oxidation. The pre\|treatment with methane has different effect on the catalytic activities of both the oxides. The methane pre\|treatment has not resulted in the change of the catalytic activity of BSCFO owing to its excellent reversibility of the perovskite structure resulting from the excellent synergistic interaction between Co and Fe in the oxide. However, the substitution with Ti on Fe\|site in the lattice makes the methane pre\|treatment have an obvious influence on the activity of the formed BSCTO oxide.
文摘TiO2-Al2O3 binary okides were prepared by gas-phase deposition of TiCly on r-Al2os support. It was found that TiO2 deposition is formd by the reaction of TiCl4 vapour with OH- group on A12O3 stirface. The TiO2 loading increases with the number of gas phase deposition operations and the tetrahedral sites of Al2O3 surface was first covered by TiO2. S1ightly decrease of surface area) pore value and average of pore diameter of TiOz-AlzO3 compared with Al2O3 was observed. In Mo/TiO2-Al2O3 catalysts Mo ealsts maally in the form of octalledla and polymer Mo7O2’ species, while no tetrahedral Mo species has been observed. The model of Mo/TiO2-Al2O3 catalyst could be imagined as a sandwich of MoO2-TiO2-Al2O3. Due to the weaker interaction between Mo species and A1zoa support in this case more Mo6+ ions in Mo/TiO2-Al2O3 sample are reduced to low valence state comparing with that of Mo/Al2O3 at 5o(f C in H2. The experimental results demonstrate that the HDS and HYD activities of Mo/TiO2-Al2O3 catalysts increase with Tioz content. It means that the full coverage of Al2o3 surface by TiO2 can driprove effectively the catalyst activity of molybdenum catalyst in hydrotreating process.
文摘XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Moδ+:δ■4) when reduc tion temperature was raised up to 673K, meanwhile sharp increases of both the irreversible and reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent. Accordingly, the active sites towards hydrogen adsorption are tentatively proposed to the low valence molybdenum species with nitrogen deficient.
文摘Carbon nanotube is found to be a novel support for the selective hydrogenation of citral in this paper. Selective hydrogenation of citral was carried out in an autoclave at 5 MPa and 323 K. The results indicate that the selectivity of the products, unsaturated alcohols, is about 86 over Pt/CNTs catalyst and 48 over Pt/XC-72 catalyst, respectively. The differential heat of CO adsorption measured by microcalorimetry is firstly used to probe surface adsorption sites of platinum catalyst supported on carbon nanotubes. The experimental results indicate that the Pt/CNTs catalyst shows a higher initial differential heat of CO adsorption(126 kJ/mol) than the Pt/XC-72 catalyst(106 kJ/mol).
