H2O2-assisted TiO2 generation during the photoelectrocatalytic process to decompose the acid green textile dye by Fenton reaction

•Cathodic H2O2 generation increased by TiO2 photoelectrocatalysis.•Methanol oxidation by photoelectrocatalysis led to higher color removal by photoelectroFenton.•Photoelectrocatalysis of methanol with subsequent H2O2 generation to decompose AG50 dye by Fenton simultaneously.•Applied potential improved methanol oxidation on TiO2 NTs photocatalyst upon UV irradiation.

TiO2 electrode was used as photo-driven anode for oxygen reduction at carbon-felt cathode to produce H2O2 used in the Fenton reaction to decompose an acid green 50 textile dye (AG50). The H2O2 generated was catalyzed with ferrous ions in the photoelectroFenton process to decompose AG50 in cathode compartment. TiO2 nanocomposite electrode was prepared by electrochemical anodization of pure Ti substrates. The results showed that TiO2 anode exhibited a porous surface and organized nanotubes annealed at 450 °C and 600 °C with anatase phase, while a surface with less porous density with compact bars was obtained at 700 °C with anatase/rutile phase. The influence of applied bias potential, concentration of methanol in the anolyte, annealing temperature of TiO2 nanocomposite and pH of the anolyte were studied on the photoelectrocatalytic degradation of methanol, whereas the catholyte composition remained unchanged for H2O2 electrogeneration. Higher mineralization of both organic compounds was obtained by increasing the annealing temperature under acidic conditions using a bias potential of 1.02 V.

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