Molecular sieve catalysts on microcalorimeter chips for selective chemical sensing

In the face of tight product tolerances and stringent environmental regulation, the impetus for developing fast and portable chemical sensors has grown significantly in recent years. Transducers have improved greatly in sensitivity and compactness, but profitable matches with materials able to imbue them with suitable sensitivities have not always progressed at a similar pace. Pellistor-type sensors in particular have enjoyed dramatic degrees of miniaturization over the years, yet suffer nevertheless from the drawback of being broadly active to all combustible species – a legacy of the nonselective nature of combustion catalysis in general. This paper describes the effects of combustion catalyst-containing zeolites on the output signals of micromachined thin-film calorimeters, and demonstrates that sensitivity to different species can be notably altered depending on the nature (e.g. pore size) of the zeolite used.