H2 production through glycerol photoreforming using one-pot prepared TiO2-rGO-Au photocatalysts

This work is focused on the optimization of the solar photo-reduction method employed for the preparation of titanium dioxide-reduced graphene oxide (TiO2-rGO) composites with the simultaneous gold nanoparticles photo-deposition. The photocatalytic performances are investigated in terms of hydrogen production by glycerol photoreforming under UV and simulated solar irradiation. Under UV light the TiO2-rGO sample prepared with two hours of solar irradiation shows the best photocatalytic activity, with an hydrogen production rate of 64 mmol H2 h−1 gcat−1, while under simulated solar light the best performance is obtained with the one-hour treated sample (1.6 mmol H2 h−1 gcat−1), due to the smaller gold particle size (around 10 nm) that allows to better exploit the Surface Plasmon Resonance (SPR) effect of gold. The Raman characterization reveals how the GO reduction degree plays a fundamental role in the photocatalytic activity of these samples. Furthermore, the presence of the gold nanoparticles allows a better control of the reduction process together with the co-catalytic action. Finally, EDX-STEM images demonstrated how this kind of preparation leads to a good gold dispersion on the catalyst surface. GO solar photo-reduction can be an easy and cheap alternative method to prepare photo-active materials having suitable properties for the photocatalytic hydrogen production.