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This study reports the performance of a self‐regenerating perovskite, LaFeCoPdO3 as a three‐way catalyst (TWC) and its use for self‐diagnostic by means of integrated Al‐doped TiO2 and LaFeCoPdO3 sensor arrays, consisted of semiconducting oxides as sensing layers and LaFeCoPdO3 as catalytic filter. Although perovskite catalyst yields a reasonable NO conversion performance at lower temperatures, it cannot fully compete with a commercial TWC under the TWC relevant temperatures and conditions. On the other hand, as‐coated duplex layer exhibits reasonable sensor property toward NO2 at 600 °C but sensor response deteriorates in NO2 + CO mixed gas environment. Ageing tests in the harsh exhaust peripherals however yield that perovskite improves the duplex layer's response through crack network and by protecting semiconducting oxide.

NO 2 emission is mostly related to combustion processes, where gas temperatures exceed far beyond 500˝C. The detection of NO 2 in combustion and exhaust gases at elevated temperatures requires sensors with high NO 2 selectivity. The thermodynamic equilibrium for NO 2 /NO ě 500˝C lies on the NO side. High temperature stability of TiO 2 makes it a promising material for elevated temperature towards CO, H 2 , and NO 2 . The doping of TiO 2 with Al 3+ (Al:TiO 2 ) increases the sensitivity and selectivity of sensors to NO 2 and results in a relatively low cross-sensitivity towards CO. The results indicate that NO 2 exposure results in a resistance decrease of the sensors with the single Al:TiO 2 layers at 600˝C, with a resistance increase at 800˝C. This alteration in the sensor response in the temperature range of 600˝C and 800˝C may be due to the mentioned thermodynamic equilibrium changes between NO and NO 2 . This work investigates the NO 2 -sensing behavior of duplex layers consisting of Al:TiO 2 and BaTi (1-x) Rh x O 3 catalysts in the temperature range of 600˝C and 900˝C. Al:TiO 2 layers were deposited by reactive magnetron sputtering on interdigitated sensor platforms, while a catalytic layer, which was synthesized by wet chemistry in the form of BaTi (1-x) Rh x O 3 powders, were screen-printed as thick layers on the Al:TiO 2 -layers. The use of Rh-incorporated BaTiO 3 perovskite (BaTi (1-x) Rh x O 3 ) as a catalytic filter stabilizes the sensor response of Al-doped TiO 2 layers yielding more reliable sensor signal throughout the temperature range.

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