am508883f_si_001.pdf (6.69 MB)
Modulation of Pore Sizes of Titanium Dioxide Photocatalysts by a Facile Template Free Hydrothermal Synthesis Method: Implications for Photocatalytic Degradation of Rhodamine B
journal contribution
posted on 2015-02-25, 00:00 authored by Shivatharsiny Rasalingam, Chia-Ming Wu, Ranjit T. KoodaliMesoporous TiO2 photocatalysts
were prepared in ethanol media by using relatively green, template
free sol–gel technique. A mild hydrothermal treatment procedure
was employed to tune the pore sizes of the materials. Comprehensive
techniques that include powder X-ray diffraction, diffuse reflectance
spectroscopy, specific surface area analysis, electron microscopy,
FT-IR, TGA, and ζ-potential measurements were used to characterize
the titania materials. Porosity (pore size and pore volume) of the
materials were found to be key factors for the variation in the rate
of photocatalytic degradation of rhodamine B; in addition to specific
surface area, and surface hydroxyl groups. An increase in porosity
permits effective transport of the dye molecules resulting in an increase
in the rate of the degradation in materials having larger pores. A
detailed electrospray ionization-mass spectrometric (ESI-MS) study
was carried out for selected materials to identify photodegraded intermediates
and products formed during the degradation of rhodamine B. In addition,
experiments were also carried out to understand the role of reactive
oxygen species (ROS). In summary, this work provides a simple way
to tune pore sizes without the use of any template and an insight
into the influence of pore size for the photocatalytic degradation
of rhodamine B.