Pseudobrookite thick films for potential application as low-temperature sensitive material in NO gas sensors

Abstract

Pseudobrookite thick films were obtained by screen printing paste composed of a 1:1.5 molar ratio mixture of starting nanopowders of hematite and anatase, glass frit and organic binder. The films were deposited on alumina substrates with interdigitated electrode geometry. Sintering at 850 °C resulted in the formation of pseudobrookite. X-Ray Diffraction (XRD) analysis showed pseudobrookite with a mixed orthorhombic and monoclinic structure and a small amount of excess rutile. Gas sensing measurements with low NO gas concentrations in air were performed using an in-house gas sensor testing setup in the temperature range 100-300 °C. On the example of one particular gas concentration, results showed that pseudobrookite exhibited a distinct response to NO already at 150 °C that further improved with increased sample temperature.