TiO₂ Nanotubes/MWCNTs Nanocomposite Photocatalysts: Synthesis, Characterization and Photocatalytic Hydrogen Evolution Under UV-Vis Light Illumination

Nanocomposite of TiO₂ nanotubes (TiO₂NTs) and multiwalled carbon nanotubes (MWCNTs) hasbeen synthesized by a hydrothermal method and firstly used in photocatalytic hydrogen production.The obtained TiO₂ NTs/MWCNTs composites were characterized by X-ray diffraction, transmissionelectron microscopy, Raman spectrum and ultraviolet-visible diffuse reflectance spectroscopy. Theexperimental results revealed that the MWCNTs were decorated with well dispersed anatase TiO₂nanotubes with a diameter of 8–15 nm. A slight blue shift and weak symmetry was observed forthe strongest Raman peak which resulted from strain gradients originating from interface integrationbetween TiO₂ nanotubes and MWCNTs. The photocatalytic activity of the as-prepared sampleswas evaluated by hydrogen evolution from water splitting using Na₂S and Na₂SO₃ as sacrificialreagents under UV-vis light irradiation. Enhanced photocatalytic activity compared with P25 hasbeen observed for the resulted samples. The nanocomposite with optimized MWCNTs content of1% displayed a hydrogen production rate of 161 μmol·h⁻¹·g⁻¹. Good photocatalytic stability of theas-synthesized samples was observed as well.