Synthesis, Characterisation of WO 3 Nanofibers and their Application in Chemical Gas Sensing
- PDF / 3,751,785 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 1 Downloads / 168 Views
0915-R04-03
Synthesis, Characterisation of WO3 Nanofibers and their Application in Chemical Gas Sensing Silvia Piperno1, Maurizio Passacantando1, Luca Lozzi1, Carlo Cantalini2, Ratna A. Phani1, and Sandro Santucci1 1 Department of Physics, University of L'Aquila, Via Vetoio, Coppito (AQ), ITALY, I-67010, Italy 2 Department of Chemistry and Materials, University of L'Aquila, Monteluco di Roio, L'Aquila, ITALY, I-67040, Italy ABSTRACT WO3 nanofibers have been produced by a simple method as electrospinnig. This is a process by which polymer nanofibers (with submicron scale diameters) can be formed when a droplet of viscoelastic polymer solution is subjected to high voltage electrostatic field. Polymer PMMA and WCl6 solution mixtures were used as precursors. The nanofiber were characterized morphologically and chemically by XPS, SEM, and XRD measurements and it was found the formation of mixed WOx/PMMA nanowires at room temperature that evolve after annealing at 300 °C towards pure WO3 nanofibers as evidenced by XPS measurements. After the characterization the nanofibers have been deposited on the sensor devices to check their gas sensing properties. They show a semiconductor-like behaviour when they are heated and wide variation of the electrical resistance when they are exposure to NO2 gas. INTRODUCTION Recently one dimensional materials have been widely studied because of their novel properties compared with the bulk corresponding properties. The low dimensionality, large area and unique electrical and magnetic properties allow a wide range of application in nanoscale science and technology. WO3 and various tungsten sub oxide (WO2 and WO3-x) nanoparticle had been intensively studied for their physical and chemical properties. WO3 has been used to construct electro chromic windows [1], optical devices [2], gas chromic sensor for the determination of NO2, O3, H2S, NH3, H2, CO [3-8]. WO3-x has sheet superconductivity which is closely related to its substructure and defect [9]. Many methods, such as laser vaporization, chemical vapour deposition and electrochemical deposition have been used to prepare various tungsten oxides. In this work, we have used electrospinning method to synthesise a novel polymer/oxide composite nanofibers. Production of synthetic filaments using electrostatics force has been known for more than one hundred years. It has been known in recent time that the electrospinning process is able of producing fibers in the submicron range.Until now the electrospinning looks the only available technique for the production of fibers with very small diameters. Electrospinning technology enables production of continuous polymer nanofibers from polymer solution or melts in high electric field. Mutual charge repulsion causes a force directly opposite to the surface tension. The charged jet is elongated and accelerated by the electric field, undergoes a variety of instabilities and is deposited on the substrate. Polymer PMMA and WCl6 solution mixtures were used as precursors. The effect of variation of
process
Data Loading...
