Interaction of light with metals in the form of surface plasmons is used in a wide range of applications in which the scattering decay channel is important. The absorption channel is usually thought of as unwanted and detrimental to the efficiency of the device. This is true in many applications, however, recent studies have shown that maximization of the decay channel of surface plasmons has potentially significant uses. One of these is the creation of electron-hole pairs or hot electrons which can be used for e.g. catalysis. Here, we study the optical properties of hetero-metallic nanostructures that enhance light interaction with the catalytic elements of the nanostructures. A hybridized LSPR that matches the spectral characteristic of the light source is excited. This LSPR through coupling between the plasmonic elements maximizes light absorption in the catalytic part of the nanostructure. Numerically calculated visible light absorption in the catalytic nanoparticles is enhanced 12-fold for large catalytic disks and by more 30 for small nanoparticles on the order of 5 nm. In experiments we measure a sizable increase in the absorption cross section when small palladium nanoparticles are coupled to a large silver resonator. These observations suggest that heterometallic nanostructures can enhance catalytic reaction rates.
In this review we discuss the evolution of surface plasmon resonance and localized surface plasmon resonance based
hydrogen sensors. We put particular focus on how they are used to study metal-hydrogen interactions at the nanoscale,
both at the ensemble and the single nanoparticle level. Such efforts are motivated by a fundamental interest in
understanding the role of nanosizing on metal hydride formation processes. However, nanoplasmonic hydrogen sensors
are not only of academic interest but may also find more practical use as all-optical gas detectors in industrial and
medical applications, as well in a future hydrogen economy, where hydrogen is used as a carbon free energy carrier.