Recyclable
Graphene Oxide-Supported Titanium Dioxide Photocatalysts with Tunable
Properties
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Abstract
A modular synthesis technique was
developed for producing graphene-supported titanium dioxide photocatalysts.
The modular synthesis allowed for simple tuning of the ratio of particle
loading on the graphene oxide (GO) surface as well as good photocatalytic
activity of the composite and quick, efficient magnetic separability.
GO flakes were used as a support for titanium dioxide nanoparticles
and SiO<sub>2</sub> insulated nano-sized magnetite aggregates. Different
composition ratios were tested, resulting in a catalyst formulation
with photocatalytic activity exceeding that of a commercial photocatalyst
by a factor of 1.2 as well as excellent recyclability, with the capability
to degrade 3 mg/L methylene blue in aqueous solution over 10 consecutive
trials with minimal loss in photocatalytic efficiency. Recovery of
the catalyst was achieved by simply exposing the nanocomposite to
a magnetic field for ∼1 minute. Furthermore, it was found that
the catalyst could be regenerated to its initial efficiency through
simple UV treatment to provide additional re-use. To highlight the
importance of the nanocomposite to the current water treatment industry,
we showed rapid degradation of pharmaceutical compounds caffeine and
carbamazepine within 60 min. The nanocomposite shows activity exceeding
that of commercial photocatalyst P25 with the added benefit of being
fully recoverable, reusable, and easy to produce. Overall, a simple
technique for producing and tuning an effective magnetically recyclable
nanocomposite was developed which should allow easy scalability and
industrial production, a factor critical for the implementation of
nano-based water treatment techniques