Photocatalytic reactivity for O2radical dot− and OHradical dot radical formation in anatase and rutile TiO2 suspension as the effect of H2O2 addition Original Research Article

Effect of crystalline structure, anatase and rutile, on the production of OHradical dot and O2radical dot− by TiO2 photocatalytic reaction was investigated. The OHradical dot 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 OHradical dot with rutile photocatalysts was significantly lower than that with anatase photocatalysts. By the addition of H2O2, the formation rate of OHradical dot 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 OHradical dot. In photocatalytic production of O2radical dot−, rutile surpassed anatase in stabilizing the produced O2radical dot−. On H2O2 addition, anatase surpassed rutile in the photocatalytic activity to produce O2radical dot− from H2O2.