Hydrogen gas sensing using platinum nanoparticles with nanogaps

In this study, we fabricated Pt nanoparticles with nanogaps on glass substrates and evaluated their electrical response to H2 gas. Pt nanoparticles with various gap sizes were exposed to H2 gas at 100 ppm, and we observed that a resistance change of 51.4% is achieved by optimizing the gap size. In conventional Pt nanostructure-based sensors, the H2 gas was detected through the resistance changes caused by electron scattering from H atoms adsorbed on the Pt surface or those diffused into grain boundaries and defects. The resistance change observed in this study was significantly larger than those observed in conventional sensors, and the above mechanism cannot fully explain the substantial resistance change. Consequently, our findings suggest that structural changes at the contact interfaces between nanoparticles contribute to the resistance change in Pt nanoparticles with nanogaps.