Efficient Charge Transfer Channels in Reduced Graphene Oxide/Mesoporous TiO₂ Nanotube Heterojunction Assemblies toward Optimized Photocatalytic Hydrogen Evolution

Abstract

Interface engineering is usually considered to be an efficient strategy to promote the separation and migration of photoexcited electron-hole pairs and improve photocatalytic performance. Herein, reduced graphene oxide/mesoporous titanium dioxide nanotube heterojunction assemblies (rGO/TiO2) are fabricated via a facile hydrothermal method. The rGO is anchored on the surface of TiO2 nanosheet assembled nanotubes in a tightly manner due to the laminated effect, in which the formed heterojunction interface becomes efficient charge transfer channels to boost the photocatalytic performance. The resultant rGO/TiO2 heterojunction assemblies extend the photoresponse to the visible light region and exhibit an excellent photocatalytic hydrogen production rate of 932.9 μmol h−1 g−1 under simulated sunlight (AM 1.5G), which is much higher than that of pristine TiO2 nanotubes (768.4 μmol h−1 g−1). The enhancement can be ascribed to the formation of a heterojunction assembly, establishing effective charge transfer channels and favoring spatial charge separation, the introduced rGO acting as an electron acceptor and the two-dimensional mesoporous nanosheets structure supplying a large surface area and adequate surface active sites. This heterojunction assembly will have potential applications in energy fields.

Keywords

• TiO₂
• photocatalysis
• mesoporous structure
• assembly
• heterojunction