Western Kentucky University
Department of Physics and Astronomy

Colloquium

Alexander Larin

Department of Physics and Astronomy
University of Louisville

"ARTIFICIAL OLFACTORY SYSTEM FOR MULTICOMPONENTAL ANALYSIS OF GAS MIXTURES"

October 09, 2017 @ 4:00 pm in TCCW 201

Abstract

Gas analysis is an important part of our world with gas sensing technology grown to be essential for various aspects of our life. The process of developing novel analytical instruments in parallel with improving conventional state-of-the-art methods for gas analysis, are primarily driven by new technological processes and ecological standards that require higher sensitivity, faster response, advanced selectivity, improved stability of modern gas analytical systems. Furthermore, there is a growing interest toward portable and semi-portable devices for gas analysis which provide similar capabilities and reliability as stationary gas analytical instruments under laboratory conditions. Developing high performance portable gas analytical instrumentation available for general public needs was the main motivation of this work. Novel approach for gas mixture analysis by using portable gas chromatograph in combination with an array of highly integrated and selective metal oxide (MOX) sensors was proposed. Simple and at the same time very efficient detector’s design allowed us to integrate four sensing elements and a micro heater on a single electronic platform (1.5 x1.5 mm), providing synchronized response from all the sensors and minimizing the total power consumption per sensing element ( < 50 mW). In this work, we successfully synthesized nanocomposite gas sensors based on SnO2 for selective detection of hydrogen sulfide, mercaptans, alcohols, ketones and heavy hydrocarbons. Different sensing elements based on nanocomposite materials such as SnO2 – TiO2, Au@SnO2, Pt@SnO2, Pd@SnO2, and Au/Pd@SnO2 were fabricated by using multi-source magnetron sputtering techniques with precise control over geometry of the sensing elements. It was demonstrated that gas sensing performance (sensitivity, selectivity, stability and time of response) of polycrystalline SnO2 can be significantly improved by modifying its surface or bulk with other metal oxides nanocrystals or noble mono or bimetal nanoparticles.