Atomic Layer Deposition of Gold Nanoparticles with Controlled Size and Distribution on Titania Support

Abstract

Nano-sized gold particles have shown unique merits in the field of catalysis, sensing and imaging, whereas their controllable synthesis with sub-nanometer size and narrow distribution on a support still remains a challenge. Herein, we developed a facile and controllable process of atomic layer deposition (ALD) using dimethyl(acetylacetonate)gold (Me 2 Au(acac)) and ozone as the precursor reactants to directly synthesize ultrafine Au nanoparticles on titania support. The size of Au nanoparticles could be precisely controlled via the modulation of depositing temperature and the counter reactant. Additionally, the dispersion of Au nanoparticles on the support is decreased by pre-calcining TiO 2 in air, which is due to the decreased surface hydroxyls concentration on support, leading to less adsorption sites of gold precursor. Moreover, we demonstrated that Au nanoparticles prepared by this method on TiO 2 could function as an effective co-catalyst for photocatalytic hydrogen evolution reaction.

The surface chemistry of the atomic layer deposition of metal thin films

“…To deliver late transition metals, many simple metal complexes were initially tested, including carbonyls, halides, and amido compounds [101], but in general larger metalorganic compounds have been preferred [12,15,17,19,21,22,24,25]. Those can be quite versatile and have afforded the development of ALD processes for the growth of metallic films of virtually all late-transition metals (Fe, Ru, Os; Co, Rh, Ir; Ni, Pd, Pt; Cu, Ag) [17,20,21,25], although there are still a limited number of precursors available for coinage metals, for Au in particular [15,102,103]. However, because of the potential complexity of their ligands, they can easily follow undesirable side decomposition steps.…”

Selected Area Deposition of High Purity Gold for Functional 3D Architectures

“…CVD studies with the Me 2 Au (acac) precursor are in good agreement with this decomposition temperature [ 43 ]. However, precursor decomposition as low as 363 K has been demonstrated with O 2 and ozone co-reactants [ 44 ]. Here we show selected area deposition can be achieved using the Me 2 Au (acac) precursor and be extended to three dimensions with sub-diffraction limit resolution (pillar diameter << laser wavelength), while yielding high purity functional gold coatings of a variety of nanostructures.…”