Synthesis of Carbon Nanotube–Anatase
TiO<sub>2</sub> Sub-micrometer-sized Sphere Composite Photocatalyst
for Synergistic
Degradation of Gaseous Styrene
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Abstract
The carbon nanotube (CNT)–sub-micrometer-sized
anatase TiO<sub>2</sub> sphere composite photocatalysts were synthesized
by a facile
one-step hydrothermal method using titanium tetrafluoride as titanium
source and CNTs as structure regulator. Various technologies including
X-ray diffraction, UV–visible absorption spectra, N<sub>2</sub> adsorption–desorption, scanning electron microscopy, and
transmission electron microscopy were employed to characterize the
structure properties of the prepared composite photocatalysts. The
results indicated that the composite photocatalysts consisted of CNTs
wrapping around the sub-micrometer-sized anatase TiO<sub>2</sub> spheres
with controllable crystal facets and that the aggregated particles
with average diameter ranged from 200 to 600 nm. The fabricated composite
photocatalysts were used to degrade gaseous styrene in this work.
As expected, a synergistic effect that remarkably enhancing the photocatalytic
degradation efficiency of gaseous styrene by the prepared composite
photocatalysts was observed in comparison with that the degradation
efficiency using pure anatase TiO<sub>2</sub> and the adsorption of
CNTs. Similar results were also confirmed in the decolorization of
liquid methyl orange. Further investigation demonstrated that the
synergistic effect in the photocatalytic activity was related to the
structure of the sub-micrometer-sized anatase TiO<sub>2</sub> spheres
and the significant roles of CNTs in the composite photocatalysts.
By controlling the content of CNTs, the content of TiO<sub>2</sub> or the temperature during the hydrothermal synthesis process, anatase
TiO<sub>2</sub> spheres with controllable crystallite size and dominant
crystal facets such as {001}, {101}, or polycrystalline could be obtained,
which was beneficial for the increase in the synergistic effect and
further enhancement of the photocatalytic efficiencies