Synthesis of Bi‐doped TiO₂ Nanotubes and Enhanced Photocatalytic Activity for Hydrogen Evolution from Glycerol Solution

Abstract

Bi-doped TiO 2 nanotubes with variable Bi/Ti ratios were synthesized by hydrothermal treatment in 10 mol•L -1 NaOH (aq.) through using Bi-doped TiO 2 particles derived from conventional sol-gel method as starting materials. The effects of Bi content on the morphology, textural properties, photo absorption and photocatalytic activity of TiO 2 nanotubes were investigated. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) observations of the obtained samples revealed the formation of titanate nanotube structure doped with Bi, which exists as a higher oxidation state than Bi 3＋ . Bi-doping TiO 2 nanotubes exhibited an extension of light absorption into the visible region and improved photocatalytic activities for hydrogen production from a glycerol/water mixed solution as compared with pure TiO 2 nanotubes. There was an optimal Bi-doped content for the photocatalytic hydrogen production, and high content of Bi would retard the phase transition of titanate to anatase and result in morphology change from nanotube to nanobelt, which in turn decreases the photocatlytic activity for hydrogen evolution.

One-Dimensional Titanium Dioxide Nanomaterials: Nanotubes

“…Hydrothermally grown TiO 2 nanotubes can be doped with various elements including chromium, manganese, cobalt, niobium, vanadium, bismuth, boron, phosphor, gadolinium, platinum, iron, and neodymium 457,458,[460][461][462][464][465][466] . Different co-doped 459,463 and tri-doped 467 TiO 2 nanotubes were also reported.…”

Influences of Doping on Photocatalytic Properties of TiO2 Photocatalyst

“…Doping with bismuth (Bi) ions can also decrease the bandgap of TiO 2 and thereby extend its absorption into the visible light region, enhancing its photocatalytic efficiency [243][244][245]. The impurity energy level from the hybrid of Bi 6s, O 2p, and Ti 3d orbitals is the cause of the red shift of the absorption edge.…”

Photocatalytic partial oxidation of methanol to methyl formate under visible light irradiation on Bi-doped TiO2viatuning band structure and surface hydroxyls

“…4, the bands at 144, 197, 399, 516 and 639 cm À1 are the Raman active fundamentals of anatase. 29,36,39,40 The three Raman bands at 144, 197 and 639 cm À1 are denitely assigned to the three E g modes, the band at 516 cm À1 is from the doublet of A 1g and B 1g modes and that at 399 cm À1 is attributed to the B 1g mode. It can be observed that the E g bands centered at 144 cm À1 , attributed to the shi of Ti-O-Ti frame of anatase, shi to higher position, the peak width is broadened and the intensity of the peaks is weakened with the increase of the Bi content, indicating poorer crystallinity and evidencing the intercalation of Bi into the lattice of anatase from another angle.…”