Convenient fabrication of carbon-doped titania nanofibresby electrospinning

& The Institution of Engineering and Technology 2010

In a previous paper, the authors prepared carbon-doped titania nanoparticles with the visible-light response via a novel controlled non-hydrolytic sol– gel approach [32]. In this Letter, the PMMA/titania hybrid nanofibres are fabricated via the electrospinning technique with the spinning solution of PMMA and a titania N,Ndimethylformamide (DMF) sol. Moreover, the carbondoped titania nanofibres with rough surfaces are obtained for the first time by thermal treatment of the as-synthesised PMMA/titania hybrid nanofibres at 4008C. In this preparation method, carbon doping and the removal of the polymer component are performed simultaneously. The morphology of the nanofibres has been investigated. The photocatalytic property of the resulted carbon-doped titania nanofibres under visible light irradiation is also evaluated using a model pollutant, methylene blue (MB), at room temperature. and the distance between the spinneret and collector was 15 cm. During the electrospinning process, the applied voltage was 20 kV and the feeding rate of the spinning solution was 0.3 ml/h. The electrospinning process was conducted in air at room temperature. The PMMA/titania hybrid nanofibres were obtained with various concentrations of PMMA solution. The carbon-doped titania nanofibres were prepared by treating the PMMA/ titania hybrid nanofibres at 4008C for 100 min.
nanotubes and nanobelts, have attracted great attention [23 – 26]. Very recently, Schmuki and co-workers synthesised several kinds of titania nanotubular layers with photoresponse in the visible region by doping of non-metal elements [27, 28]. They found that nitrogen-doped titania nanotubes prepared by ion implantation exhibited strongly enhanced photocurrent response in both the UV and the visible range. The self-organised titania nanotubular array doped with carbon by thermal acetylene treatment was also explored and noticeably this kind of titania material displayed a significant photoresponse over the whole range of visible light up to the near-IR region [28]. The electrospinning technique has been proven to be a relatively convenient and versatile method for fabricating ultrafine fibres and many researchers have successfully prepared titania nanofibres or nanotubes by this method [29 – 31]. It is easy for electrospinning to fabricate nanofibres with large surface area by the removal of the polymer component, which is important for the photocatalytic application of titania nanofibres. Furthermore, nanofibres and non-woven fabrics are beneficial for the recycling of photocatalysts compared with nanoparticles. However, there ison of titania nanofibres with visible-light activity. Micro & Nano Letters, 2010, Vol. 5, Iss. 1, pp. 42– 48 doi: 10.1049/mnl.2009.0103
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Abstract: Carbon-doped titania nanofibres have been fabricated by the electrospinning technique using polymethyl methacrylate (PMMA) solution and a titania non-aqueous sol followed by calcination. PMMA was used as a base polymer in the electrospinning solution to assist the formation of nanofibres and subsequently removed by the thermal treatment. The nanofibres were characterised using various techniques. The diameter of the titania nanofibres is in the range of 200 – 300 nm according to scanning electron microscopy observation. X-ray photoelectron spectroscopy results demonstrate that the carbon doping into titania nanofibres is achieved via calcining the PMMA/titania hybrid nanofibres at 4008C. The carbon-doped titania nanofibres exhibit good photocatalytic activity under visible light irradiation.
X.X. Wang1 X.M. Song1 G.Q. Wang2 H.T. Wang1 Q.G. Du1
Department of Macromolecular Science, Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Fudan University, Shanghai 200433, People’s Republic of China 2 Innovative Systems & Materials Laboratory, Shanghai Research Institute, Hitachi (China) Research & Development Corporation, Shanghai 200020, People’s Republic of China E-mail: wanght@
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Introduction
Titania nanomaterials have attracted much attention for their extensive applications in dye-sensitised solar cells [1, 2], photocatalysis [3–6], gas sensing [7, 8], environmental cleaning and protection [9]. However, the photocatalytic efficiency of titania is very low under sunlight irradiation because it merely responds to the UV light and it is known that the UV region is only approximately 4% of the total radiation of the solar spectrum. Therefore, the titania materials sensitive to the visible light have received more and more scientific and technological interest. Recently, it has been demonstrated by many research groups that titania doped with non-metal elements such as nitrogen [10–13], fluorine [14, 15], sulphur [16, 17] or carbon [18–22] shows response to visible light and higher photocatalytic activity under solar light irradiation. It is also confirmed that carbon-doped titania has a surprising activity in the degradation of 4-chlorophenol by visible light [20]. For the distinctive geometries, novel physical and chemical properties and the potential applications in nanodevices, drug delivery, nanosensors and microelectronics, one-dimensional chemical nanostructures, such as nanorods, nanowires, 42