Enhanced hydrogen production by carbon-doped TiO2 decorated with reduced graphene oxide (rGO) under visible light irradiation

Enhancing visible light utilization by photocatalysts, avoiding electron-hole recombination, and facilitating charge transfer are three major challenges to the success of sustainable photocatalytic systems. In our study, carbon-doped TiO2 was synthesized with decoration of reduced graphene oxide (C-TiO2/rGO) to form a hybrid nanocomposite that exhibits excellent photocatalytic activity and longevity. Morphology, chemical and colloidal stability, crystallinity, surface compositions and band structures were systematically assessed. The results revealed that the hybrid C-TiO2/rGO had a band gap of 2.2 + 0.2 eV and crystallite sizes of 0.9-2 nm in diameter. Transmission electron microcopy (TEM) images showed that C-TiO2 particles attached to the carbon sheet of rGO. Under irradiation of 135 mW cm(-2) at 400-690 nm with methanol as electron donor, C-TiO2 and C-TiO2/rGO yielded incredibly high H-2 production rates of 0.67 +/- 0.12 to 1.50 +/- 0.2 mmol g(-1) h(-1), respectively, which were greater than those of other titanium hybrid catalysts such as C-TiO2/Pt. rGO not only greatly improved the photocatalytic activity but also led to greater stability of H-2 production compared to C-TiO2. This work lays groundwork toward the design of novel visible light-driven photocatalytic systems for harnessing solar energy and environmental applications.