Self-adhesive graphene oxide-wrapped TiO2 nanoparticles for UV-activated colorimetric oxygen detection

Abstract

We first report on the synthesis of graphene oxide-wrapped TiO2 nanoparticles (GO-TiO2 NPs) as a self-adhesive photocatalyst for UV-activated colorimetric oxygen detection. Methylene blue (MB), a redox dye for colorimetric oxygen indication, strongly adsorbed onto GO-TiO2 NPs by both electrostatic and pi-pi stacking interactions. The chemical attraction between GO and MB significantly decreased dye leakage, which is a serious problem of colorimetric oxygen indicators; MB leaching from GO-TiO2-based film was fivefold lower than that from conventional TiO2-based film. This novel MB/GO-TiO2/glycerol/hydroxyethyl cellulose film was successfully bleached by UV irradiation, and it regained its blue color rapidly in the presence of oxygen, demonstrating its useful functionality as a UV-activated colorimetric oxygen indicator.