Biomass-derived carbon deposited TiO 2 nanotube photocatalysts for enhanced hydrogen production.

In this study, titanium oxide nanotubes (TiO 2 NTs) were deposited on the surface of activated carbon (AC) by varying the wt% of AC. The physicochemical properties of synthesized TiO 2 NTs-AC nanocomposites were analysed by various characterization techniques such as XRD, FT-IR, Raman, DRUV-vis, HR-TEM, XPS, PL, and N 2 physisorption. The FT-IR, EDX, and XPS analyses proved the existence of interaction between AC and TiO 2 NTs. This study found that as the content of AC increases, the surface area and pore volume increase while the energy bandgap decreases. The TiO 2 NTs-AC nanocomposite with 40% AC exhibited a surface area of 291 m 2 g -1 , pore volume of 0.045 cm 3 g -1 and half pore width = 8.4 Å and had a wide band gap energy (3.15 eV). In addition, the photocatalytic application of the prepared nanocomposites for photocatalytic H 2 production was investigated. The H 2 was produced via photo-reforming in the presence of a sacrificial agent (methanol) under sunlight irradiation. It was found that the prepared TiO 2 NTs-AC nanocomposite with 40% AC acted as an efficient photocatalyst for aqueous-methanol reforming under various optimization conditions. Approximately 18 000 μmol -1 hydrogen gas was produced via aqueous-methanol reforming under optimized conditions (catalyst dose = 100 mg, temperature = 25 °C, time = 12 hours, vol. of methanol = 20% (v/v), and pH = 7). The reusability of the TiO 2 NTs-AC nanocomposite was also investigated for 5 consecutive cycles, and the results suggested only a slight decline in efficiency even after the fifth cycle. This study demonstrates the ability of an activated carbon deposited TiO 2 NT catalyst to produce hydrogen effectively under sunlight.