The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed...The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and unstable activity. Depending on the calcination temperature, one, two, or three of the following Ni-containing species, NiO, Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction （TPR） and X-ray diffraction （XRD） results. Their reducibility decreased in the sequence： NiO〉Ni2.44Ti0.72Si0.07O4〉NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ~C were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.展开更多
Homogeneous Ni2+-doped titania gel was synthesized by a sol-gel process, and the xerogel was then ob-tained through aging and drying, leading to the formation of Ni/TiO2 nanocomposite after heat treatment under a suit...Homogeneous Ni2+-doped titania gel was synthesized by a sol-gel process, and the xerogel was then ob-tained through aging and drying, leading to the formation of Ni/TiO2 nanocomposite after heat treatment under a suitable reducing atmosphere. The resulting nanocomposite was characterized by TGA-DSC, TEM, XRD and BET methods. The results show that the structure and grain size of the nanocomposites could be manipulated by altering the heat-treatment conditions, and that the nanocomposite possesses a mesoporous structure with a pore radius of ca. 28 nm and a specific surface area of 49.1 m2.g-1. It is demonstrated that the nanosized Ni dispersion in the titania matrix significantly affects the anatase-rutile phase transformation.展开更多
文摘The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and unstable activity. Depending on the calcination temperature, one, two, or three of the following Ni-containing species, NiO, Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction （TPR） and X-ray diffraction （XRD） results. Their reducibility decreased in the sequence： NiO〉Ni2.44Ti0.72Si0.07O4〉NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ~C were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.
基金support from Anhui Natural Science Foundation(Grant No.00046403)“973”Key Project of the National Fundamental Research of China,Nanomaterials and Nanostructure(Grant No.G19990645)Creative Program of Chinese Academy of Sciences in Nano—structured Materials Field
文摘Homogeneous Ni2+-doped titania gel was synthesized by a sol-gel process, and the xerogel was then ob-tained through aging and drying, leading to the formation of Ni/TiO2 nanocomposite after heat treatment under a suitable reducing atmosphere. The resulting nanocomposite was characterized by TGA-DSC, TEM, XRD and BET methods. The results show that the structure and grain size of the nanocomposites could be manipulated by altering the heat-treatment conditions, and that the nanocomposite possesses a mesoporous structure with a pore radius of ca. 28 nm and a specific surface area of 49.1 m2.g-1. It is demonstrated that the nanosized Ni dispersion in the titania matrix significantly affects the anatase-rutile phase transformation.
