Photocatalytic reactivity for O2− and OH radical formation in anatase and rutile TiO2 suspension as the effect of H2O2 addition

Effect of crystalline structure, anatase and rutile, on the production of OH and O2− by TiO2 photocatalytic reaction was investigated. The OH radical free from the TiO2 surface was monitored by the fluorescence intensity of 2-hydroxyl terephthalic acid produced by the reaction with terephthalic acid. Superoxide radical was detected by the chemiluminescence probe method with luminol. Formation rate of OH with rutile photocatalysts was significantly lower than that with anatase photocatalysts. By the addition of H2O2, the formation rate of OH was significantly increased for rutile and for anatase mixed with rutile by 10–20%, while pure anatase showed an opposite tendency. We suggest that the adsorption structure of H2O2 on the rutile TiO2 surface is preferable to produce OH. In photocatalytic production of O2−, rutile surpassed anatase in stabilizing the produced O2−. On H2O2 addition, anatase surpassed rutile in the photocatalytic activity to produce O2− from H2O2.

Effect of crystalline structure, anatase and rutile, on production of OH and O2− by TiO2 photocatalysis was studied. Anatase surpassed rutile in the production of OH with water, while by addition of H2O2 the OH formation rate on rutile was significantly improved. Rutile surpassed anatase in stabilizing O2−, while by addition of H2O2 anatase shows higher activity to produce O2−. Figure optionsDownload as PowerPoint slide