Comparison of the effects generated by the dry-soft grinding and the photodeposition of Au and Pt processes on the visible light absorption and photoactivity of TiO2

The influence of dry-soft grinding and photodeposition of gold (Au) or platinum (Pt) in the improvement of the photoactivity of TiO2 synthesized by an integrated sol-gel and solvothermal method was studied. TiO2 was modified by a dry-soft grinding process in a planetary ball mill (TiO2(G)). Subsequently, Au or Pt particles were photodeposited in both unmodified TiO2 and TiO2(G) obtaining Au-TiO2, Pt-TiO2, Au-TiO2(G), and Pt-TiO2(G) materials. The photoactivity of the materials was evaluated in the phenol photodegradation under simulated solar radiation. Pt-TiO2 showed the greatest degree of photoactivity improvement in comparison with TiO2 and TiO2-P25. The dry-soft grinding process led to a high photocatalytic activity of TiO2(G) that was similar to Pt-TiO2 activity as consequence of a slight increase in the crystallinity in TiO2(G) due to an additional anatase formation in comparison with TiO2. However, further photocatalytic improvement in TiO2(G) were not achieved with the addition of Au or Pt. Therefore, the dry-soft grinding treatment and noble metal deposition led to similar improvements in the photocatalytic activity of TiO2 for phenol oxidation.