Few Layer Graphene/TiO2 Composites for Enhanced Solar-Driven H2 Production from Methanol

Here, the elaboration of few layer graphene/TiO2 photocatalytic composites (FLG/TiO2) with FLG loadings from 0.5 to 11 wt % is presented. Contrary to the commonly used (reduced) graphene oxide obtained by long and harsh condition synthesis, FLG was synthesized by a simple, fast, efficient, and eco-friendly exfoliation method. The enhancement of defective/functionalized site density for the attachment of TiO2 species was achieved via the calcination process at 450 degrees C. The nanocomposites were evaluated toward H-2 production from methanol under artificial solar light irradiation, without the use of a co-catalyst. It was observed that the best activities are provided by the composites with the lowest loading: 0.5 and 1.0 wt % FLG/TiO2 that are 2-3 times more efficient than reference and commercial TiO2. The photocatalytic activity of the composites was correlated to their surface area, morphological, structural, optical properties, and kinetics of free electron mobility properties. The enhanced activity is attributed to a higher surface area, better photogenerated charge separation thanks to electrons' delocalization and trapping onto graphene layers well interfaced with TiO2 nanoparticles but also to additional FLG visible light absorption properties and charge carriers' generation. The impact of enhanced FLG edge defects/functionalities is reflected as well via selected analysis and hydrogen generation.