The Working Effect Of TiO₂ Photoinduced Carrier Transferring And Its Application In Photocatalysis

TiO₂ has been an important studied topic in the world due to its extensive applications. In this work, the working effect of photo induced carriers and their transferring in TiO₂-based photocatalysts are studied and the photocatalysis based on this process is aslo analyzed. The splitting of Fermi energy level (|F_n-F_p|) and carrier transferring are very important in the heterogeneous photocatalysis. This research will develop some new routes for the TiO₂ photocatalysts.Since the surface electronic structure of TiO₂ is very important in photocatalysis, this research studied the surface electronic structure by using PL spectra. The effect of grain size, UV illumination, pH, Ag⁺, MO and MB on the surface structure and PL spectrum shape, which can be used to judge the photoinduced carrier transferring to surface states were studied. The surface states play two different roles for the photoinduced carriers, one is surface recombination center, the other is surface active centers.Based on the carrier's surface transferring, this research developed a method to calculate the value of |F_n-F_p| and the photocatalytic rate constant by using the photoconductivity, and it can be used in the study of photocatalytic mechanism. n and K_const is two important parameters related to the TiO₂, TiO₂ surface and target photocatalytic substance, which can be used to explain the photocatalysis successfully. The photocatalytic rate constant has a good relationship with the |F_n-F_p| value calculated from photoconductivity. It has been illustrated that |F_n-F_p| value is an important thermodynamic parameters in the TiO₂ photocatalysis, which suggests that some important physical course needed to be considered in the TiO₂ photocatalysis.The bandgap is adjusted by N and V doping in TiO₂, the relationship between bandgap, |F_n-F_p| and photocatalytic efficiency were studied on the N and V-TiO₂, and the photocatalytic efficiency on the N- and V-TiO₂ structure was also study. Furthermore, the relationship of incident light intensity, |Fn-Fp| with photocatalytic efficiency was studied. The experiment result also revealed that the |F_n-F_p| value is a key character factor in the TiO₂ photocatalysis.The two-photon absorption course based on the sub-band in conduction band in TiO₂ was stuided and results show that this course is a feasible way in...