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Date Published: 24 Feb 2006
FINE-TUNING OF CERAMIC-BASED CHEMICAL SENSOR
The vital need to develop fast responding sensors for toxic gases before their
concentration reaches lethal levels is driven by events like the Sago coal mine disaster which took
place on Jan 2, 2006 in Tallmansville, West Virginia where 12 miners died. Key interests of Dr.
Abdul-Majeed Azad, Chemical and Environmental Engineering, University of Toledo, in this area
have led to the development of a novel technique for detecting low levels of CO using tungsten
oxide (WO3) and molybdenum oxide (MoO3).
Challenges such as high selectivity, enhanced sensitivity and short response time which
are highly dependant on the nano-features of materials used in solid-state ceramic-based
chemical sensors are some of the aspects that have been addressed in this research. This has
been augmented by the reason that nanofeatures such as dimensionality and size give us a
better understanding of the material behavior such as their chemical, mechanical and optical
This technique is based on rigorous thermodynamic considerations of the metal/metal
oxide coexistence and has resulted in a novel redox technique to enhance sensor behavior. By
modulating the oxygen partial pressure across the equilibrium metal/metal oxide (M/MO)
proximity line, formation and growth of new oxide surface on an atomic/submolecular level under
conditions of `oxygen deprivation' has been achieved in potential sensor materials.