Mutual-stabilization in chemically bonded graphene oxide–TiO2 heterostructures synthesized by a sol–gel approach

We study the structure of the photocatalytic graphene oxide-titanium dioxide (GO-TiO2) nanocomposites prepared by in situ sol-gel nucleation and growth of TiO2 on GO sheets. Fourier transform-infrared (FTIR) and X-ray photoelectron (XPS) spectra of these composites indicate that the GO sheets and the TiO2 nanoparticles interact through Ti-O-C bonds. This chemical interaction is strong enough to ensure mutual stabilization during thermal annealing, and thereby GO inhibits TiO2 crystallization. In addition, thermal reduction of GO nanoribbons anchored to TiO2 nanoparticles occurs at a higher temperature and with a lower released energy than in the pure GO powder. Understanding of the mutual-stabilization mechanisms is critical for the rational design of GO-TiO2 photocatalysts.