[Study of photoelectrocatalytic oxidation of benzoic acid]

This study reports the photoelectrocatalytic oxidation of benzoic acid in a three-electrode photoelectroreactor. The effects of the anode bias potential, the atmosphere of reaction and the basis material for photocatalyst preparation on the removal efficiency of benzoic acid were researched. The photoelectrocatalysis was compared with photolysis, photocatalysis and electrolysis. The results of the experiments indicated the removal efficiency of benzoic acid after the photoelectrocatalytic oxidation process for 1 h could be more than 85%, much higher than the efficiency of photolysis (48%), photocatalysis (30%) and electrolysis (nearly having no effect). The synergetic effect of the photoelectricity was obvious. The working electrode and the counter electrode were arranged as two concentric columns whose diameters were different. The results showed that this kind of arrangement mode was very effective. In nitrogen atmosphere the removal efficiency of benzoic acid could be 98% when TiO2/Ti acted as the anode of the photoelectrocatalytic oxidation process for 1 h, much better than the TiO2/Al did (85%). While in oxygen atmosphere the two kinds of electrodes were both effective and the removal efficiency of benzoic acid could approach 100%.