Detecting Benzene Vapor via a Low-Cost Nanostructured TiO2 Sensor

Cost-effectively detecting benzene, a human carcinogen, at occupationally and atmospherically relevant concentrations would benefit individuals at risk of exposure. This paper presents the development of a titania (TiO2) nanotube-based sensor array that has a high surface area, is highly sensitive, and operates at room temperature using simple, portable instrumentation. An n-type TiO2 nanotube was synthesized through electrochemical anodization in an electrolytic solution of ammonium fluoride-ethylene glycol and oxygen annealed at 500 degrees C for up to 8 hours. The nanotube sensor had a bandgap (Eg) of similar to 2.6 eV, and it was operated at a bias voltage of +1.5 V. The response of the sensor to benzene vapor was measured using an amperometric technique at room temperature, and when exposed to benzene, the sensor exhibited a decrease in current, as expected for an n-type metal oxide semiconductor. The sensor response was proportional to benzene concentration over a range of 100-400 ppb. A sensing mechanism based on Fermi level changes caused by band bending has been explained for this benzene sensor.

Automated summary

This paper presents the development of a titania nanotube-based sensor array for cost-effectively detecting benzene, a human carcinogen, at occupationally and atmospherically relevant concentrations. The sensor has a high surface area, is highly sensitive, and operates at room temperature using simple, portable instrumentation. The sensing mechanism is explained based on Fermi level changes caused by band bending for this benzene sensor.