Nanocomposites and nanomaterials

Nanosized Ce-doped SnO2 nanocomposites as perspective material for adsorption semiconductor sensors

G. Fedorenko, L. Oleksenko, N. Maksymovych, O. Ripko, G. Skolyar
Department of Chemistry, Taras Shevchenko National University of Kyiv,
Volodymyrska str. 64/13, Kyiv-01601, Ukraine.
E-mail: georgf@ukr.net

Cerium dioxide is widely used for creation of oxygen membranes in the fuel cells and as an active component in oxidation catalysts due to mobility of the oxygen ions in the CeO2 crystal structure. Significant catalytic activities in oxidation reactions (e.g. CO and H2 oxidation) make the use of the cerium dioxide promising for increase in sensitivities of adsorption semiconductor gas sensors. Besides the cerium addition can provide control of the morphology of SnO2 nanoparticles that can also contribute to the sensor response formation.
In this work a synthesis of nanosized sensor composites material 3 wt.% Ce-SnO2 with an average particle size of 9 nm was developed. It was found that an average value of the electrical resistance of the sensors based on this material falls in range 7-55 MOhms. Addition of Sb to the material can change both the electrical resistance and response to hydrogen of the sensor due to formation of a donor layer corresponded to Sb5+ in the SnO2 band structure. The increase in the number of conduction electrons increases conductivity of the sensor and could make direct influence on the amount of chemisorbed oxygen and, thus, on the value of the sensor response (Fig.1).
	Fig.1. Dependences of the sensor response to 44 ppm H2 on temperature for the sensors based on nanosized CeO2-SnO2-Sb2O5 materials with different Sb content.