The aims of this work was to obtain TiO2 by Pulsed Laser deposition (PLD), coated it with Co3O4, obtained by PLD and sol-gel techniques, and compare their performance for the oxygen evolution reaction (OER) in alkaline media.
The experimental method for the PLD of TiO2 was reported before1. The deposition of the Co3O4 was performed by PLD in the same conditions used for the titanium oxide films. Also the Co3O4 were deposited on TiO2 by sol-gel using cobalt carbonate, and glycerol to form the gel and then heated at 573K.
The TiO2 and TiO2/Co3O4 films were tested for the photocatalytic oxygen evolution reaction in alkaline media with a1000 watts xenon lamp and with day light. A double cell with a quartz window, a platinum counter electrode and an Hg/HgO/KOH0.5M reference electrode connected to a Potensiostat galvanostat EG&G 273A was used.
The X-Ray Diffraction analysis shows the formation of the titanium oxide in anatasa phase, the band gap determined by UV-Vis analysis was 3.2 this value was not changed by the deposition of the thin film of Co3O4 by PLD or sol-gel techniques. The formation of the Co3O4 film over the TiO2 was determined by Raman spectroscopy and Rutherford backscattering
The electrophotocatalytic activity of the TiO2/Co3O4 films was better for the OER than the TiO2. It was very close for the same thickness films obtained either by PLD or sol-gel techniques. The best result for the OER was for the thinner film of Co3O4 onto TiO2 obtained by PLD.