Zeolite Modified Vanadium Pentoxide Sensors for the Selective Detection of Volatile Organic Compounds

Abstract

Exposure to volatile organic compounds can lead to asphyxiation, pneumonia like conditions, comas, seizures and irreversible lung, kidney and central nervous system damage. Volatile organics are additionally extremely flammable and explosive, making their early detection in the immediate environment increasingly important. Metal oxide semiconductor (MOS) gas sensors present a potential technology to detect such gases.

Metal oxide semiconducting (MOS) gas sensors represent a cheap, robust and sensitive technology for detecting volatile organic compounds. An array of five thick film MOS gas sensors was fabricated, based on vanadium pentoxide inks. Production took place using a commercially available screen printer, a 3 x 3 mm alumina substrate containing interdigitated electrodes and a platinum heater track. V₂O₅ inks were modified using zeolite beta, zeolite Y, mordenite & ZSM5 admixtures. Sensors were exposed to three common reducing gases, namely acetone, ethanol, and toluene, and a machine learning technique was applied to differentiate between the different gases. Sensors produced strong responses to all gases. Zeolite modified sensors were found to increase the responsiveness of the sensors compared to umodified V₂O₅ in a number of cases. Machine learning techniques were incorporated to test the selectivity of the sensors. A high level of accuracy was achieved in determining the class of gas observed.