Abstract:

By thermal decomposition, Ti/SnO₂-Sb electrodes modified with metals on Ti substrates were prepared. The morphology and crystal structure of the electrodes were analyzed by SEM and XRD. The stability and electric catalytic activity were studied by strengthening the electrode life and the electric catalytic experiment. The degradation rate of the electrodes was analyzed by dynamic equation, the degradation mechanism of nitrobenzene was explored with mass spectrum, and the concentration of OH · was measured by salicylic acid capturing hydroxyl radicals with high performance liquid chromatography. The experimental results show that metal doping improved the surface morphology, changed the diffraction peak intensity of SnO₂, prolonged the electrolytic life, and ameliorated the catalytic ability of the electrodes. The degradation of nitrobenzene was identified with quasi first order reaction dynamics equation. The aniline absorption peak was generated on the mass spectrogram at top 5-10 min, after 15 min there was no other absorption peak indicated that the nitrobenzene degraded rapidly after deoxidizing to aniline. The higher concentration of free radicals was, the faster nitrobenzene degradation rate would be. Since it reacted for 60 min, the OH· concentration of the blank electrode fell by one-fifth, comparing to the one mixed with Cu.

Key words: Semiconductor electrode, Electric catalytic oxidation, Nitrobenzene, Metal doping