Physical vapor deposition (PVD) is typically used to obtain homogenous thin-films. Adi Salomon, Bar-Ilan University, Ramat-Gan, Israel, and colleagues have used PVD to create highly porous three-dimensional (3D) networks of metals.

The researchers used a porous silica aerogel as a support and found that this material promotes the growth of a disordered nanoporous metal network during PVD. The resulting materials consisted of particulated ligaments of uniform thickness in the range of 100 nm and pore sizes in the range from a few tens to a few hundred nanometers. Contrary to their bulk counterparts, the 3D metals showed strong colors reminiscent of those observed in plasmonic metal nanoparticles.

The team demonstrated the photocatalytic activity of 3D silver under white light irradiation and suggests the use of the materials for applications in catalysis and energy devices. The researchers also point out that their large-scale materials are easier to separate from reaction solutions than nanoparticles.

• Direct Fabrication of 3D Metallic Networks and Their Performance,
  Racheli Ron, David Gachet, Katya Rechav, Adi Salomon,
  Adv. Mater. 2016.
  DOI: 10.1002/adma.201604018