X-ray photoelectron spectroscopy(XPS) and extended X-ray absorption fine structure(EXAFS) were used to characterize the structure of the mixture of molybdenum oxide and anatase calcined at 723 K. The results indicate ...X-ray photoelectron spectroscopy(XPS) and extended X-ray absorption fine structure(EXAFS) were used to characterize the structure of the mixture of molybdenum oxide and anatase calcined at 723 K. The results indicate that molybdenum oxide can disperse onto the surface of anatase(TiO 2) and the dispersion threshold is 11.2 mg in per gram of MoO 3 or 4.8 Mo atoms/nm 2 TiO 2. When the content of MoO 3 is below the dispersion threshold, MoO 3 species is in highly dispersed state interacting strongly with TiO 2 support and in discrete tetrahedral coordination, [MoO 4], on the surface of TiO 2. When the MoO 3 loading is above this value, MoO 3 exists in both dispersed phase and crystalline phase. MoO 3 in dispersed phase is still a discrete [MoO 4] tetrahedron; MoO 3 in crystal phase is in octahedral coordination.展开更多
基金the National Natural Science Foundation of China(No.2 97330 80 ) and the Major State Basic ResearchDevelopment Program(No.G2 0 0 0 0 775 0 3)
文摘X-ray photoelectron spectroscopy(XPS) and extended X-ray absorption fine structure(EXAFS) were used to characterize the structure of the mixture of molybdenum oxide and anatase calcined at 723 K. The results indicate that molybdenum oxide can disperse onto the surface of anatase(TiO 2) and the dispersion threshold is 11.2 mg in per gram of MoO 3 or 4.8 Mo atoms/nm 2 TiO 2. When the content of MoO 3 is below the dispersion threshold, MoO 3 species is in highly dispersed state interacting strongly with TiO 2 support and in discrete tetrahedral coordination, [MoO 4], on the surface of TiO 2. When the MoO 3 loading is above this value, MoO 3 exists in both dispersed phase and crystalline phase. MoO 3 in dispersed phase is still a discrete [MoO 4] tetrahedron; MoO 3 in crystal phase is in octahedral coordination.
