Anodic electrocatalytic behavior of graphite supported TiO2 towards the generation of hydroxyl radicals

The electrocatalytic mechanism of TiO2 towards anodic oxidation is mostly described as the electron-hole theory which seems limited and incomplete for its electrocatalytic application. This study focused on the anodic oxidation behavior of graphite supported TiO2 (TiO2/C). The results reveal that theTiO(2)/C anode generates H2O2 as the intermediate which decomposed to center dot OH indirectly from 1.0 V to 1.2 V. At higher potentials (1.4 V similar to 2.0 V), the center dot OH generation is mainly attributed to H2O decomposition directly but inhibited by H2O2 in high concentration. The EPR analysis on oxygen defects establishes the relationship between the oxygen defect and the center dot OH generation experimentally. Together with the in-situ Raman experiments, the mechanisms for the center dot OH generation on TiO2/C anode are further correlated with oxygen vacancy and Ti-OH structure. This study provides a fundamental insight into the electrocatalytic behavior of TiO2 towards anodic oxidation, which is vital to its application in EAOPs.