Photocatalytic degradation of naphthalene by electrospun mesoporous carbon-doped anatase TiO₂ nanofiber mats

We have fabricated partially aligned free-standing mesoporous pure anatase TiO₂ nanofiber mats (TiO₂-NF) for photocatalysis by electrospinning on a rotating drum collector using a blend of titanium isopropoxide (Ti(OiPr)₄), with a carrier polymer, polyvinylpyrrolidone (PVP) in acetic acid and ethanol. Calcination removes PVP and generates mesoporous TiO₂-NF with fiber diameters in the range of 25-75 nm by optimizing the electrospinning parameters such as electric field strength, polymer concentration, and flow rate of solution, etc. The band gap energy of TiO₂ nanofibers from the UV-vis absorption spectra is found to increase with an increase in the calcination temperature, thus allowing band gap engineering for different applications. The surface morphology, phase composition, crystallinity, surface area, and porosity of the TiO₂-NF are also investigated. We demonstrate the efficient and reusable photocatalytic action of the partially aligned pure electrospun TiO₂-NF and residual carbon containing TiO₂-NF mats with an average fiber diameter ∼40 nm in the photocatalytic degradation of a polycyclic aromatic hydrocarbon (PAH) dye, naphthalene. Small carbon residue (2.54%) containing TiO₂-NF is found to be about twice as efficient as the pristine TiO₂-NF in photodegradation of a PAH dye, but the effectiveness declined at higher carbon content.