TiO₂-Graphene Nanocomposites. UV-Assisted Photocatalytic Reduction of Graphene Oxide

TLDR

The study introduces a UV‑assisted photocatalytic method to reduce graphene oxide and produce photoactive graphene‑semiconductor composites. UV‑irradiated TiO₂ transfers electrons to graphene oxide in ethanol, reducing it while preserving exfoliated sheets and enabling composite formation. The reduction shifts the suspension from brown to black and decreases the lateral resistance of cast films by an order of magnitude.

Abstract

Graphene oxide suspended in ethanol undergoes reduction as it accepts electrons from UV-irradiated TiO2 suspensions. The reduction is accompanied by changes in the absorption of the graphene oxide, as the color of the suspension shifts from brown to black. The direct interaction between TiO2 particles and graphene sheets hinders the collapse of exfoliated sheets of graphene. Solid films cast on a borosilicate glass gap separated by gold-sputtered terminations show an order of magnitude decrease in lateral resistance following reduction with the TiO2 photocatalyst. The photocatalytic methodology not only provides an on-demand UV-assisted reduction technique but also opens up new ways to obtain photoactive graphene-semiconductor composites.