Enhanced photocatalytic H2 generation on noble metal modified TiO2 catalysts excited with visible light irradiation

Photocatalysts were prepared by the deposition of noble metal nanoparticles (Au, Pt, Rh or Ru) on different commercially available titanias. The photocatalytic performance of these catalysts was studied for the evolution of H-2 during excitation with visible light. Experiments were carried out in irradiated suspensions containing various organic compounds. Noble metal nanoparticles can promote the lowering of the overvoltage of H+ reduction. The noble metal nanoparticles were deposited onto the TiO2 surface by in situ chemical reduction in a quantity of 1 wt%. Three aspects were considered: (i) the photocatalytic performance of different bare TiO2 deposited with Pt; (ii) the effect of the deposition of Au, Pt, Rh or Ru nanoparticles onto the TiO2 surface; and (iii) choosing the most suitable H-2 production supporting organic compound. The rate of H-2 evolution proved to be strongly dependent on the quality of TiO2 powder and the presence of different organics. The applied noble metal was also an efficiency determining factor during these photocatalytic reactions. With the best combination of the above mentioned circumstances, we achieved promising results to be able to effectively harvest the energy of sunlight.