Low-temperature prototype hydrogen sensors using Pd-decorated SnO2 nanowires for exhaled breath applications

The synthesis and integration of a compact, highly sensitive, and inexpensive gas sensor for breath analysis have attracted considerable attention because of painless application, non-invasiveness, and ability to diagnose diseases during early stages. In this study, we introduced the on-chip growth of SnO2 nanowire (NW)-based gas sensor to analyze the low concentration of H2 gas for exhaled breath applications. We decorated the Pd catalyst on the surface of SnO2 NWs to enhance gas-sensing performance. Comparative results revealed that Pd decoration enhanced the H2 gas response at low operating temperature range (250-300 °C). Moreover, the Pd-decorated SnO2 NW sensor exhibited good response to H2 gas at considerably low temperature of 150 °C, whereas the bare SnO2 NWs cannot respond. Finally, the packaged sensor was tested at different supplied powers to various H2 concentrations ranging from 10 to 100 ppm. Gas selectivity toward CO2 and ethanol gases was examined. Results demonstrated that the prepared gas sensor package is suitable for breath gas analysis.