Boosting photocatalytic water splitting of TiO2 using metal (Ru, Co, or Ni) co-catalysts for hydrogen generation

Abstract The photocatalytic activity of titanium dioxide (TiO 2 ) nanoparticles toward hydrogen generation can be significantly improved via the loading of various metals e.g., Ru, Co, Ni as co-catalysts. The metal co-catalysts are loaded into TiO 2 nanoparticles via different deposition methods; incipient wet impregnation (Imp), hydrothermal (HT), or photocatalytic deposition (PCD). Among all of the tested materials, 0.1 wt% Ru–TiO 2 (Imp) provided the highest initial hydrogen catalytic rate of 23.9 mmol h −1 g −1 , compared to 10.82 and 16.55 mmol h −1 g −1 for 0.3 wt% Ni–TiO 2 (Imp) and 0.3 wt% Co–TiO 2 (Imp), respectively. The loading procedures, co-catalyst metals type, and their loading play a significant role in elevating the photocatalytic activity of pristine TiO 2 semiconductors toward hydrogen generation. Redox transition metals e.g., Co and Ni exhibit comparable photocatalytic performance to expensive elements such as Ru.