Graphite-supported TiO2 for 4-nitrophenol degradation in a photoelectrocatalytic reactor

Amorphous TiO2, prepared at room temperature through a sol–gel method implementing hydrolysis of TiCl4, has been supported on graphite rods and then annealed at 673 K. In this way graphite was completely covered by a porous anatase TiO2 layer, with an external thickness of about 1 μm, with graphite pores completely filled by the semiconductor particles. The obtained electrode was structurally characterized by SEM microscopy coupled to EDAX mapping and by Raman spectroscopy. A Pyrex annular reactor was designed in order to test the prepared electrodes for the photoelectrocatalytic degradation of 4-nitrophenol, a target pollutant dissolved in aqueous conductive solution. The continuous reactor worked in total recirculation mode and the degradation runs were carried out by applying near UV-light, bias or both energy sources. The influence of flow rate, initial 4-nitrophenol concentration and applied potential on the degradation rate was studied.