Photocatalytic activity of TiO2 based composite films by porous conjugated polymer coating of nanoparticles
Introduction
Photocatalysis has attracted worldwide research interest because of its potential ability solar energy [1]. Titania as one of the most promising photocatalysts has been investigated for its attractive applications in water splitting and mineralization of toxic organic substances [2], [3], [4]. Photocatalysts using this oxide have several advantages such as high efficiency, good stability, ready availability, and nontoxicity. However, because of its large band gap (3.2 eV), titania absorbs only UV light and this limits its optical performance. To extend its absorption to the visible range of the solar spectrum, attempts to synthesize new materials with large absorption bands have been carried out [5], [6].
The use of conjugated polymer doped TiO2 has showed that the photocatalytic performance of TiO2 could be improved under visible light [7], [8], [9]. The conjugated polymer/TiO2 composites are usually obtained by in-situ polymerization, and seldom loaded on support, limiting the usage as well as the re-use of the obtained photocatalyst [10]. On the other hand, composites with a porous structure are interesting for their, photocatalytic activity because of the high surface/volume ratio, which enhances the photocatalytic performance [11], [12], [13].
In this paper, a new method for preparing porous conjugated unsaturated polymer/TiO2 composite deposited on glass substrates is developed by using anatase TiO2 sol and polyvinyl alcohol (PVA) as a precursor. The TiO2 sol was prepared with tetra-butyl titanate at low temperature (70 °C), and by combining freeze drying and heat-treatment techniques, porous-polyvinyl alcohol/titanium dioxide (P-PVA/TiO2) composites with visible light activity were prepared and characterized. The photocatalytic activity of the P-PVA/TiO2 composites was investigated by studying the degradation of phenol solution.
Section snippets
Experimental
Tetrabutyl titanate (TBOT), absolute ethanol (EtOH), acetic acid (AcOH), acetylacetone (Acac), and phenol were purchased at Chengdu Kelong Chemical Reagents Factory (China) and used as received. Polyvinyl alcohol (PVA) with polymerization degree of 1700 and hydrolytic degree of 99% was supplied by Sichuan Vinylon Factory (Chongqing, China).
100 ml deionized water and 0.3 ml concentrated HCl were mixed and stirred at 70 °C in a three-necked flask. A mixture solution of EtOH, AcOH and TBOT was then
Characterization results
Fig. 2 shows the SEM micrographs of P-PVA/TiO2. It can be seen that the obtained composite films show a porous aspect and the polymer and the nanoparticles were intimately mixed (Fig. 2a). The surface of the composite film (Fig. 2b) contains numerous small cavities, which favor the adsorption and degradation of the dye solution.
The X-ray diffraction patterns (XRD) of P-PVA/TiO2, PVA/TiO2 and pure TiO2 are presented in Fig. 3. For TiO2 spectrum, the peaks at 2θ=25.3°, 37.8°, 47.8°, 54.2° and
Conclusion
We have investigated composites using TiO2 nanoparticles in a conjugated PVA matrix to be used in photocatalytic applications. The composite materials have been synthesized by a simple method combing freeze-drying and heat-treatment using TBOT as titanium source and PVA as precursor of conjugated polymer. We have shown that using P-PVA/TiO2 composites extended the photo-response of TiO2 from UV to visible part of sunlight and significantly improved the absorption of the material. In addition,
Acknowledgments
The authors are grateful to the National Natural Science Foundation of China (Grant nos. 50573052, and 51173116) for supporting this research. They also thank R. Michaud for technical assistance in measuring the film thickness.
References (19)
- et al.
Surf. Sci. Rep.
(2008) - et al.
Water Res.
(2010) J. Hazard. Mater.
(2011)Appl. Catal. B—Environ.
(2010)- et al.
Appl. Catal. A-Gen.
(2015) Appl. Catal. B—Environ.
(2015)- et al.
J. Colloid Interface Sci.
(2014) - et al.
Appl. Catal. B—Environ.
(2014) - et al.
Appl. Surf. Sci.
(2014)
Cited by (27)
The effects of terminal groups on the structure and photocatalytic performance of imine-linked conjugated polymers
2023, Journal of Photochemistry and Photobiology A: ChemistryAntifouling nanocomposite polymer coatings for marine applications: A review on experiments, mechanisms, and theoretical studies
2022, Journal of Materials Science and TechnologyMyth or reality? A disquisition concerning the photostability of bismuth-based photocatalysts
2022, Journal of Environmental Chemical EngineeringPolymer immobilized TiO<inf>2</inf> microparticles for photocatalytic degradation of caffeine
2022, Materials Today: ProceedingsCitation Excerpt :The author concluded that this method has a potential to be used for removing emerging organic contaminants like personal care products and pharmaceuticals. Y. Song et al. developed a new method by depositing polymer/TiO2 particles on glass substrates [35]. Freeze drying and heat treatment methods used for the preparation of PVA/TiO2 composites resulted in the extension of the photo-response of the catalyst from UV to visible part of sunlight, which enhanced the contaminant material absorption.