Interaction, Non-crystalline Structure and Catalysis Property on the Interface of Five Binary Transition Metal Oxides (I) Suggestion of Interface Non-crystalline Dispersion and Bulk Crystal Residual Ratio

The interaction and non-crystalline spontaneous dispersion at the interface of five systems of transition metal binary oxide, namely, TiO2(anatase)-MoO3, MoO3-V2O5, Fe2O3-MoO3, WO3-MoO3 and ZrO2-MoO3 containing 0-100wt% MoO3 respectively, were characterized by XRD, BET, FT-IR. The five systems were prepared by dry mixing and grinding up at room temperature, and then calcining at appropriate temperatures below melting point of two component oxides(500℃/5h). XRD quantitative analysis and extrapolation of crystal phase content indicate that each component oxide disperses spontaneously to form a non-crystalline phase at interface, and has a dispersed threshold value (the maximum dispersion capacity). BET measurements show the specific surface area of all samples are much smaller(3.71-11.3m2/g) than that of the supports such as 7-Al2O3 SiO2 and TiO2 gel etc. The dispersed threshold values of MoO2 (0.33-1.43g·10-2cm-2) determined by XRD and BET in the present paper are far greater than the monolayer dispersion capacity of MoO3 (0.117g·10-2cm-2) calculated from TANG's model of O2- close-packed mono-layer dispersion and also larger than MoO3 monolayer dispersion capacity(0.169g·10-2cm-2) calculated from the spherical octahedron model suggested in our ensuing paper. Such larger dispersed threshold value in the much smaller specific surface area signifies non-monolayer dispersion and/or chemical reaction at interface. By means of FT-IR spectra and its differential spectra, the new species of non-crystalline phase at interface and its characteristic absorption bands are discovered for the first time, and these bands are correlated to molecular structure, such as IR characteristic absorption bands of non-crystalline phase MoO3 appear at 960 and 826-828 cm-1.