Rapid response microsensor for hydrogen detection using nanostructured palladium films

Abstract

Most palladium thin film based hydrogen gas sensors have response and recovery times that are too long to make them useful in vehicular and stationary gas leak detection applications. In contrast, a nanostructured palladium thin film based microcantilever (MC) hydrogen gas microsensor is reported herein with near ideal response characteristics for use in these hydrogen economy related applications. Specifically, a 3 s response time and a 10 s recovery time have been measured for these sensors in contrast to previous sensor response measurements of several to tens of minutes using Pd thin film and MC based sensing techniques. The much reduced response time observed in the present study are attributed to a galvanic displacement technique and a gas conditioning protocol that produces a nanostructured, porous film that rapidly adsorbs and desorbs H 2, allowing rapid equilibration with the H 2 concentration in the surrounding air. The galvanic displacement process and gas phase conditioning offer a novel approach at creating structured surfaces that have not been reported for MC devices. Additionally, these sensors have very low H 2 detection thresholds, wide dynamic range and very good selectivity relative to common interferents.