Core–shell-structured carbon nanofiber-titanate nanotubes with enhanced photocatalytic activity

•We synthesize the core–shell-structured carbon nanofiber-titanate nanotubes.•Titanate nanotubes are formed during the alkaline hydrothermal treatment.•Carbon nanofiber-titanate nanotubes show superior photocatalytic activity.•The BET surface area was increased by the alkaline hydrothermal treatment. Core–shell materials have been developed extensively because of their advanced properties and multifunctionality. Many approaches involving different synthesis techniques have been used for the preparation of various core–shell nanostructures. In this study, we synthesized core–shell-structured carbon nanofiber (CNF)-titanate nanotubes (TiNT) by electrospinning, carbonization, and subsequent alkaline hydrothermal treatment. The CNF core could act as a support, and the TiO2-decorated TiNT shell could act as a photocatalyst. TiNT shells with diameters of several hundreds of nanometers and composed of 10-nm-diameter nanotubes are formed on the CNF surface. The formation of TiNTs on the CNF surface was observed using SEM, HR-TEM, XRD, and XPS analyses. Core–shell-structured CNF-TiNTs exhibited efficient photocatalytic activities for CH3CHO oxidation, which was attributed to the existence of photocatalytically active TiO2-TiNT composites on the CNF surface, which could easily absorb UV light. Additionally, the surface area increase as a result of the alkaline hydrothermal treatment may also be responsible for the efficient photocatalytic activity of core–shell-structured CNF-TiNTs.