Degradation Of Cyclohexane And Acetone And Study Of Doped Theory On Carried Titanium Dioxide

Immobilized TiO₂ thin film electrode deposited on porous nickel and carbon/graphite sheet were prepared by Sol-Gel method and were characterized by XRD and SEM. Using the thin film electrode as working electrode, a novel system of gas phase-photoelectrocatalysis is formed by comparted the cathode and anode with high polymer solid electrolyte Nafion. A reactor was designed based on the need of research, using 9W and 4W UV 1amp (365nm) as light source, In this reactor the photodegradation and photoelectrocatalytic degradation of cyclohexane and acetone was studied. The effects of some factors such as the coating layers of TiO₂, calcinations temperature, the suitable external voltage, the volume ratio between water vapor and specimen and the irons doping were researched. The photocatalytic efficiency of TiO₂ was compared between difference of prepared method and difference of carried catalyst as well.The degradation of the objective matter in gas-phase was analyzed by gas chromatography by testing its peak area. To the degradation of cyclohexane, the experiment results show that the most degradation rate is obtained when the coating layers of TiO₂ are 3, the volume ratio between water vapor and specimen is 20:1 or 30:1, the suitable external voltage is 20V. Catalytic activity was also enhanced by irons doped. The final production was confirmed by Infra-Red Spectra. And the cyclohexane was oxidation to the production of hexanediol and CO₂. To the degradation of acetone, the efficiency of degradation which was self-prepared by the material of TiOSO₄ is lightly higher than P25. It is possible to offer an industry way to prepare photocatalysis of TiO₂.The apparent rate constant of photocatalytic and photoelectrocatalytic degradation reaction is the first order, and could be described by Longmuir-HinshelWood equation. In the degradation of cyclohexane, the kinetic constant k of photocatalytic reaction is 8.74×10^-3g/m³Â·min, and the Longmuir K is 1.1445m³/g.Photocatalytic theory that TiO₂ was doped by irons is studied with first principle. The band gap, Fermi level, density of states of TiO₂ doped by N, Fe(â…¢), Pt(â…¥) and La(â…¢) have been simulated by using the plane wave pseudo potentials(PWPP) for discussing the theory of photocatalytic activity. The calculation shows that the HOMO and the LUMO are mainly composed of the 3d orbits of Ti and the 2p orbits of O. Stability of TiO₂ doped by N are enhanced by 2s orbits of N in valence band (VB). The band gap of N-doped TiO₂ is narrowed as follow: the independent energy band above valence band and energy band with 0.9eV broad range under conduction band (CB) are introduced. On the other hand, Fermi level is displaced into valence band to make optic absorption transfer to the high level. To TiO₂ doped by Fe(â…¢), Pt(â…¥) and La(â…¢), Eg of TiO₂ is narrowed after doped because it is formed few energy band to make optic absorption widened to the zone of visible-light. Thus the activity of photocatalysis is enhanced by the higher light electrons and the lower Fermi energy.