Ultrasensitive Chemiresistors Based on Electrospun TiO₂ Nanofibers

Abstract

Nanostructured semiconducting metal oxides and particularly single nanowire devices offer exceptional gas sensitivity but at the expense of statistical variations and excessive noise levels. In this study TiO2/poly(vinyl acetate) composite nanofiber mats were directly electrospun onto interdigitated Pt electrode arrays, hot pressed at 120 degrees C, and calcined at 450 degrees C. This resulted in a novel multiple nanowire network composed of sheaths of 200-500 nm diameter cores filled with readily gas accessible approximately 10 nm thick single-crystal anatase fibrils. TiO2 nanofiber sensors tested for NO2, in dry air, exhibited exceptional sensitivity showing with, for example, a 833% increase in sensor resistance when exposed to 500 ppb NO2 at 300 degrees C, consistent with a detection limit estimated to be well below 1 ppb. Unusual response patterns were observed at high NO2 concentrations (> 12.5 ppm), consistent with n to p inversion of the surface-trap limited conduction facilitated by the high surface-to-volume ratio of this material.

Photocatalytic Degradation of Oil using Polyvinylidene Fluoride/Titanium Dioxide Composite Membrane for Oily Wastewater Treatment

“…In specific, photocatalysis based on titanium dioxide (TiO 2 ) has involved a great deal of consideration due to its functional properties such as chemical and thermal stability and strong mechanical properties (Yu et al, 2009). In order to enhance the adhesion between the TiO 2 with membrane, and to further increase the efficiency of the membrane, pre-treatments such as hot press have been used (Kim et al, 2013). Recently, mechanical pressure was applied to break outer sheaths, thereby exposing the membrane accomplishing a high surface area (Liu, Chu, & Ding, 2004).…”

The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

“…Titanium samples in two different grain sizes: UFG titanium prepared by HPT and coarse-grained titanium were used. Since TNTs also have wide applications in other areas such as photocatalytic devices [29], electronics [30], solar cells [31] and sensors [32], a study of the anodization behaviour of UFG titanium may also provide insights relevant for these applications.…”

The Effect of PVAc Solution Viscosity on Diameter of PVAc Nanofibres Prepared by Technology of Electrospinning

“…The precursor nanofibers are usually fabricated by technology of electrospinning from PVAc solution together with appropriate well thermally decomposable metal salt. This precursor is then calcined when inorganic nanofiber or nanowhiskers are formed [1,2]. Nanomaterials made of pure metals or their oxides are prepared according condition of calcination.…”

“…PVAc solutions are usually used for their production. But commonly used solvents like dimethylformamide, ketones or alcohols [1,2,5] are not fully environmentally acceptable because of their toxicity. Another technological disadvantage is in their flammability.…”