Abstract
Photoelectrochemical behavior of the zinc oxide electrode prepared from sintering of zinc oxide powders at the temperature of 900 - 1200°C was investigated for the purpose of application of this electrode to water purification. Photoanodic fading of dyes (Methylene Blue, Crystal Violet, Congo Red) in aqueous solutions on the zinc oxide electrode was examined. In this case, the photoelectrochemical cell consisted of the zinc oxide photoanode in 0.1 M Na2SO4 solution containing 10 micro M dye (volume: 100 ml) and graphite cathode in 10 mM Fe2(SO4)3- 0.1 M Na2SO4 solution (volume: 100 ml) under light irradiation (wavelength: 365 nm, intensity: 30 mW/cm2). Although the electrode sintered at 900°C showed a low photocurrent quantum efficiency, 8 %, mainly due to the many boundaries on the surface, 80 % of the initial concentration of Methylene Blue faded after 6 hours irradiation. The electrode sintered at 1200°C showed 80 % of photocurrent quantum efficiency and caused the fading of Methylene Blue with 86 % of initial concentration after 6 h irradiation. The comparison of responses between photoelectrode and photocatalysis was also checked for the sintered zinc oxide samples.
