Construction Of Nano-oxide Arrays Micro-electrode And Study Of Novel Catalytic Properties

The photoelectrocatalytic oxidation technique has been paid more and more attention for the advantages of less energy cost, mild reaction condition, easy operation and less secondary pollution, so it is abroad researched in the field of environment pollution control now. The traditional TiO₂/Ti electrode is fabricated, composited TiO₂ film electrode and TiO₂ nanotubes electrode are photoanodes. The photo-electrochemical properties of different electrodes are studied and the photo-electrocatalytic degradation of azo dye-Acid Orange 7 (AO7) species with different electrodes in aqueous solution is investigated in the reactor designed by ourselves.The main results show, the man-sized TiO₂, TiO₂-SnO₂ semiconductor photocatalyst can be obtained by the sol-gel processing using tetrabutyl titanate as a precursor. Crystalline phase and surface appearance of TiO₂, TiO₂-SnO₂ crystal could be obtained by XRD and AFM analysis, the samples prepared in this experiment are anatase, and the average size of TiO₂, TiO₂-SnO₂ particles in the thin film are 20nm and 15nm, respectively. The photo-electrochemical properties of TiO₂, TiO₂-SnO₂ film electrodes are studied, and the IPCE of TiO₂ and TiO₂-SnO₂ film electrode are 10.4% and 19.9% respectively. The AO7 dye degradation efficiency of photo-electrocatalysis is found higher than that of electrocatalysis, photolysis and photocatalysis with TiO₂-SnO₂ film electrode at the same conditions. The photo-electrocatalytic degradation of AO7 species in aqueous solution over the mentioned composite electrode is investigated under the effect factors such as bias potential, the initial AO7 concentration, the initial pH value in solution, concentration of Na₂SO₄ etc. Under the maxmium conditions, bias potential is 0.8V, pH is 2.06, concentration of Na₂SO₄ is 0.1 mol/L, 99% of AO7 is bleached.Vertically aligned nanotubes arrays of titanium oxide are fabricated on the surface of titanium substrate by direct anode oxidation with HF being the supporting electrolyte. The top-opened TiO₂ nanotubes are well aligned and organized into high-density uniform arrays, with diameter from 60 to 90 nm. IPCE of TiO₂ nanotubes electrode is 36.8%. The degradation of AO7 dye in aqueous solution with TiO₂ nanotubes electrode is carried out using different processes. A significant photoelectrochemical synergetic effect is observed. By applying a biasing potential of 0.8 V to the photoanode, a bleaching of 83% at λ=484 nm and a degradation of 66% at λ=310 nm are obtained for AO7 dye. The result indicates photo-electrochemical property is significantly improved for TiO₂ nanotubes electrodecompared with the film electrodes of TiO2 and TiO2-SnO2. It is also found that nearly 78% of AO7 dye at X,=484 nm is bleached over T1O2 nanotubes electrode, whereas 61%, 70% of AO7 dye are bleached by employing T1O2 film electrode and TiO2-SnO2 film electrode, respectively. The kinetics constant of PEC degradation of AO7 using T1O2 nanotubes electrode is 48.7% higher than that using TiC>2 film electrode formed by sol-gel method.