Microhotplate catalytic sensors based on porous anodic alumina: Operando study of methane response hysteresis

Catalytic pellistor-type sensors are widely used for the analytical detection of flammable/explosive gases. Further improvement of the characteristics of the sensors can be achieved by the development of miniature sensing elements based on planar microhotplates, which allows one to decrease the power consumption substantially. Here we demonstrate the microhotplate catalytic sensors based on anodic aluminium oxide supports for methane detection. The sensor response approaches the value of 15 mV/vol. % CH4 at the optimal supply voltage. A wide hysteresis in sensor response is observed during the cycling of the supply voltage. This phenomenon is studied under operando conditions using X-ray diffraction and thermogravimetry. The obtained results have a significant impact on the development of optimal working regimes, and the production of planar catalytic sensors on porous supports.