Abstract
In this study, high specific surface areas (SSAs) of anatase titanium dioxide (TiO2) quantum dots (QDs) were successfully synthesized through a novel one-step microwave–hydrothermal method in rapid synthesis time (20 min) without further heat treatment. XRD analysis and HR-TEM images showed that the as-prepared TiO2 QDs of approximately 2 nm size have high crystallinity with anatase phase. Optical properties showed that the energy band gap (Eg) of as-prepared TiO2 QDs was 3.60 eV, which is higher than the standard TiO2 band gap, which might be due to the quantum size effect. Raman studies showed shifting and broadening of the peaks of TiO2 QDs due to the reduction of the crystallite size. The obtained Brunauer–Emmett–Teller specific surface area (381 m2 g−1) of TiO2 QDs is greater than the surface area (181 m2 g−1) of commercial TiO2 nanoparticles. The photocatalytic activities of TiO2 QDs were conducted by the inactivation of Escherischia coli under ultraviolet light irradiation and compared with commercially available anatase TiO2 nanoparticles. The photocatalytic inactivation ability of E. coli was estimated to be 91% at 60 µg ml−1 for TiO2 QDs, which is superior to the commercial TiO2 nanoparticles. Hence, the present study provides new insight into the rapid synthesis of TiO2 QDs without any annealing treatment to increase the absorbance of ultraviolet light for superior photocatalytic inactivation ability of E. coli.
Highlights
Titanium dioxide (TiO2) is a significant nanomaterial which has attracted a considerable attention because of its distinctive royalsocietypublishing.org/journal/rsos R
We report the synthesis of the agglomeration-free anatase TiO2 quantum dot, for the first time, by using TiCl3 and NaOH by microwave–hydrothermal method toward the photocatalytic deactivation of Escherichia coli under UV light source
All the diffractions peaks in TiO2 quantum dots (QDs) and commercial nanoparticles are well matched and indexed to anatase phase, and are in good agreement with standard JCPDS card no. 89-4921
Summary
Titanium dioxide (TiO2) is a significant nanomaterial which has attracted a considerable attention because of its distinctive royalsocietypublishing.org/journal/rsos R. TiO2 nanoparticles prepared by a sol–gel method are amorphous in nature; a calcination process is required to achieve the crystallinity Another factor that plays a key role in increasing the photocatalytic activity is the larger SSA of TiO2. Deng et al [31] synthesized anatase TiO2 QDs with surface hydroxyl groups and particle size below 3 nm via a new synthetic route (sol–gel) They have reported that the reaction was completed in a Teflon-lined autoclave, and kept in an oven at 90°C for 1 day. We report the synthesis of the agglomeration-free anatase TiO2 quantum dot, for the first time, by using TiCl3 and NaOH by microwave–hydrothermal method toward the photocatalytic deactivation of Escherichia coli under UV light source. The resulting QDs show remarkably high photocatalytic inactivation of E. coli as compared with commercially available TiO2 nanoparticles
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