Improvement and stabilization of optical hydrogen sensing ability of Au-Pd alloys.

Formation of metal hydrides is a signature chemical property of hydrogen and it can be leveraged to enact both storage and detection of this technologically important yet extremely volatile gas. Palladium shows particular promise as a hydrogen storage medium as well as a platform for creating rapid and reliable H optical sensor devices. Furthermore, alloying Pd with other noble metals provides a technologically simple yet powerful way of enacting control over the structural and catalytic properties of the resultant material.

Metamaterial for Hydrogen Sensing.

A hydrogen sensor based on plasmonic metasurfaces is demonstrated to exhibit the industry-required 10 s reaction time and sensitivity. It consists of a layer of either Y or WO sandwiched between a top Pd nanodisk and a Au mirror at the base. The phase change layer (Y, WO) reacts with hydrogen, and the corresponding change of the refractive index (permittivity) is detected by the spectral shift of the resonance dip in reflectance at the IR spectral window.