Graphite Oxide as a Photocatalyst for Hydrogen Production from Water

TLDR

Graphite oxide was synthesized via a modified Hummers' method to produce a semiconductor photocatalyst with a bandgap of 2.4–4.3 eV. The GO photocatalyst, with a 0.42 nm interlayer spacing, steadily produces hydrogen from methanol–water mixtures and pure water under UV or visible light without a cocatalyst, and although photo‑induced oxygen loss narrows its bandgap and raises conductivity, it does not compromise stable H₂ generation, demonstrating the promise of graphitic materials for solar‑driven water splitting.

Abstract

Abstract A graphite oxide (GO) semiconductor photocatalyst with an apparent bandgap of 2.4–4.3 eV is synthesized by a modified Hummers' procedure. The as‐synthesized GO photocatalyst has an interlayer spacing of 0.42 nm because of its moderate oxidation level. Under irradiation with UV or visible light, this GO photocatalyst steadily catalyzes H 2 generation from a 20 vol % aqueous methanol solution and pure water. As the GO sheets extensively disperse in water, a cocatalyst is not required for H 2 generation over the GO photocatalyst. During photocatalytic reaction, the GO loses some oxygen functional groups, leading to bandgap reduction and increased conductivity. This structural variation does not affect the stable H 2 generation over the GO. The encouraging results presented in this study demonstrate the potential of graphitic materials as a medium for water splitting under solar illumination.