The hydrogenation of graphene oxide (GO)–TiO₂ composites with a quasi-shell–core structure was performed in the temperature range of 250–550 °C. All the synthetic hybrid materials displayed enhanced photocatalytic performances and the highest photoactivity was obtained by the hybrid material prepared at 450 °C due to the formation of a p–n junction and appropriate charge mobility. The semiconductor behaviour of the resultant reduced graphene oxide (RGO) in the composites had a crossover from p-type to n-type when the hydrogenated temperature increased from 450 °C to 550 °C.