Minimizing Graphene Defects Enhances Titania Nanocomposite-Based Photocatalytic Reduction of CO2 for Improved Solar Fuel Production

TLDR: It is shown that nanocomposites based on the less defective solvent-exfoliated graphene exhibit a significantly larger enhancement in CO(2) photoreduction, especially under visible light.

Abstract: With its unique electronic and optical properties, graphene is proposed to functionalize and tailor titania photocatalysts for improved reactivity. The two major solution-based pathways for producing graphene, oxidation–reduction and solvent exfoliation, result in nanoplatelets with different defect densities. Herein, we show that nanocomposites based on the less defective solvent-exfoliated graphene exhibit a significantly larger enhancement in CO2 photoreduction, especially under visible light. This counterintuitive result is attributed to their superior electrical mobility, which facilitates the diffusion of photoexcited electrons to reactive sites.