Carbon-based Composite Materials as Photocatalyst for Photo-Reforming of Organics to Obtain H2

The photo-reforming of ethanol, glycerol or microplastics (polyethylene terephthalate or polylactic acid) aqueous suspensions of semiconductors have been carried out under UV and natural solar light irradiation to obtain hydrogen. Heterogeneous photocatalysts used in this reaction are pristine Nb2O5 and TiO2 as well as their composites with graphene (G) or graphene oxide (GO). All materials gave rise to hydrogen under both UV and solar radiation and the H2 productivity was found to be higher for the composite materials compared to bare semiconductors and it was further increased in the presence of Pt (1% w/w) used as co-catalyst. Results of H2 productivity show that TiO2 composite photocatalysts are more active than the Nb2O5 ones. The aim of this study is to improve the sustainability of the hydrogen production process by using carbonaceous materials to fabricate heterostructures and identifying the optimal weight ratio between the two constituents. Furthermore, this work aims to study the influence of the type of substrate, used as hole scavenger, in the photo-reforming process for hydrogen production. The highest performance was achieved under UV light irradiation by using, as photo-catalyst, the composite containing TiO2 and G in a mass ratio of 10:1 w/w, in the presence of Pt and for the photo-reforming of aqueous ethanol solutions. In these conditions, the productivity of H2 was of 311 mmol·h?¹·g?¹ with an apparent quantum efficiency (AQE) of 100% under UV light. Instead, under natural solar irradiation the highest productivity of H2 of 25 mmol·h?¹·g?¹ was reached during the photo-reforming of aqueous glycerol solutions.