Platinum Decorated Palladium Nanowires for Room‐Temperature Hydrogen Detection

The use of hydrogen as an energy carrier will require low‐cost, low‐power hydrogen sensors. Toward this goal, penta‐twinned palladium nanowires (Pd NWs) are synthesized and fabricated sensors from them by drop‐casting. Pd NWs drop‐cast onto an interdigitated electrode (IDE) gave a response of 0.3% to 1 vol.% H 2 , with response and recovery times of 12 and 20 s, respectively. However, they exhibited a negative response (decreased resistance) at low H 2 concentrations. Pd NWs on a paper substrate provided a tenfold higher response to 1 vol.% H 2 , with response and recovery times of 10 s each, but still exhibited negative response at low H 2 concentration. Exposing the Pd NW‐on‐paper sensor to ozone‐generating UV light degraded the PVP used in Pd NW synthesis, eliminating the reverse sensing response, and providing a response of 5% to 1 vol.% H 2 , with response and recovery times of 15 s. This allowed reliable H 2 detection down to 100 ppm H 2 . Finally, coating the Pd NWs with a small amount of Pt (<5%) reduced the response and recovery times to 5 s by catalyzing H 2 dissociation. This work provides a path to low‐cost sensors to enable the safe use of H 2 as an energy carrier.