RESUMO
Achieving stability with highly active Ru nanoparticles for electrocatalysis is a major challenge for the oxygen evolution reaction. As improved stability of Ru catalysts has been shown for bulk surfaces with low-index facets, there is an opportunity to incorporate these stable facets into Ru nanoparticles. Now, a new solution synthesis is presented in which hexagonal close-packed structured Ru is grown on Au to form nanoparticles with 3D branches. Exposing low-index facets on these 3D branches creates stable reaction kinetics to achieve high activity and the highest stability observed for Ru nanoparticle oxygen evolution reaction catalysts. These design principles provide a synthetic strategy to achieve stable and active electrocatalysts.
RESUMO
Bimetallic nanostructures show exciting potential as materials for effective photothermal hyperthermia therapy. We report the seed-mediated synthesis of palladium-gold (Pd-Au) nanostructures containing multiple gold nanocrystals on highly branched palladium seeds. The nanostructures were synthesized via the addition of a gold precursor to a palladium seed solution in the presence of oleylamine, which acts as both a reducing and a stabilizing agent. The interaction and the electronic coupling between gold nanocrystals and between palladium and gold broadened and red-shifted the localized surface plasmon resonance absorption maximum of the gold nanocrystals into the near-infrared region, to give enhanced suitability for photothermal hyperthermia therapy. Pd-Au heterostructures irradiated with an 808 nm laser light caused destruction of HeLa cancer cells in vitro, as well as complete destruction of tumor xenographs in mouse models in vivo for effective photothermal hyperthermia.