Semiconducting metal oxides (MOX) such as SnO2 are an industry-standard material for chemiresistive sensing. However, many MOX-based gas sensors suffer from poor sensitivity, limited selectivity—particularly in the presence of water vapor—and insufficient stability. To address these shortcomings, catalytically active noble metals, such as Pd, are loaded onto the MOX materials to form noble metal-loaded MOX nanocomposites. In this work, we focus on Pd-loaded SnO2 (Pd/SnO2) due to their promising sensitivity to and selectivity for CO and CH4. Pd/SnO2 nanocomposites with varying Pd/Sn nominal molar ratios are synthesized following a facile wet chemical reduction-annealing process and characterized structurally and chemically. Drop-casting methods are used to deposit the nanocomposites onto interdigitated electrodes to form fully functioning sensors. The Pd/SnO2 sensors show enhanced sensitivity and selectivity towards carbon monoxide. To improve sensor to sensor variations, the effects of various components in the Pd/SnO2 ink formulation as well as the deposition parameters such as temperature are investigated and will be reported.
Project currently funded by: Industry Sponsor