Efficient H2 production by photocatalytic water splitting under UV or solar light over variously modified TiO2-based catalysts

This paper focused for the first time on the comparison between three different approach to modify the chemico-physical properties of TiO₂-based photocatalysts and their effect in the H₂ production by photocatalytic water splitting both under UV and solar light irradiation, under the same experimental conditions. The application of pulsed laser irradiation to aqueous TiO₂ suspensions (first approach) induced structural transformations both on the bulk and on the surface of TiO₂, boosting the H₂ production, under UV light irradiation, of almost three times (20.9 mmol/g_cat·h) compared to bare TiO₂ (7.7 mmol/g_cat·h). The second strategy was based on a templating method to obtain TiO₂ with a macroporous structure to favour an efficient light absorption process inside the material pores, thus allowing a high H₂ production (0.64 mmol/g_cat·h) under solar light irradiation. This performance was further enhanced when the macroporous TiO₂ was coupled with CeO₂ or W (third approach). In the latter case the H₂ production increased to 0.72 mmol/g_cat·h for macroporous TiO₂CeO₂ and to 0.82 mmol/g_cat·h for macroporous TiO₂W. This work highlights how it is possible to tune the TiO₂ photocatalytic properties with easy and green procedures to obtain environmental friendly catalyst for hydrogen production.