Synthesis and Properties of Au Hydride

Abstract

The generation of chemical species from gases, noble metals and light interacting with localized surface plasmons represents a new paradigm for achieving low energy sustainable reaction pathways. Here, we demonstrate that the dissociation reaction of H2 meditated by the decay of localized surface plasmons of gold nanoparticles leads to the generation of a new material as detected by a change in the optical properties of the gold nanostructures. The effective permittivity measured by in situ spectroscopic ellipsometry shows a blue‐shift of 0.02 eV in the surface plasmon resonance, demonstrating the plausible formation of a metastable gold hydride layer on the surface of nanoparticles following the dissociation of H2. The formation of this gold hydride through the interaction of gold with atomic H is supported by first‐principles simulations. These calculations do not indicate a significant charge transfer upon hydrogenation of the (111) surface but rather large Friedel charge oscillations within the gold layer. Moreover, our blue‐shift is produced by the formation of a hydride leading to changes in critical band gaps in the electronic structure. For a coverage of 11%, the calculated peak of the imaginary part of the ZZ‐component of the dielectric tensor undergoes a blue shift of 28 nm from a hydrogen free peak at 574 nm.