Palladium–Platinum Alloy Nanoribbon/Nanosheets for Room-Temperature Hydrogen Detection

Hydrogen is being extensively investigated as a carbon-free energy carrier, particularly for fuel-cell vehicles and long-term energy storage. Because H2 can form explosive mixtures in air at concentrations as low as 4%, its safe use requires inexpensive, low-power sensors capable of reliable detection. Here, we investigated ribbon-like palladium–platinum nanostructures, referred to as PdPt nanoribbon/nanosheet hybrid structures (PdPt NR/NSs), for room-temperature chemiresistive H2 sensing. Sensors were fabricated by drop-casting dispersions of the PdPt NR/NSs onto interdigitated electrodes. The sensor resistance increased upon exposure to H2 because of hydrogen uptake by the PdPt NR/NSs and formation of a hydride phase with higher resistivity than the hydrogen-free alloy. The best-performing sensor, Pd5Pt8, was prepared using a 5:8 Pd:Pt precursor mass ratio, which yielded a measured Pd:Pt atomic ratio of approximately 1.3:1. This sensor showed a response time of 16 s and a response of 6.0% to 1 vol% H2 in air. H2 concentrations as low as 100 ppm were readily detected while maintaining a positive resistance response. These results demonstrate the potential of PdPt NR/NS architectures for low-power H2 detection at ambient temperature.