Polymer/Trimer/Metal Complex Mixtures as Precursors of Gold Nanoparticles: Tuning the Morphology in the Solid-State

Abstract

The pyrolysis of several physical mixtures of AuCl(PPh3) with polymeric [NP(O2C12H8)]n or cyclic N3P3(O2C12H8)3 phosphazenes, formed as solid powders or films with different molar ratios, have been studied under air and at 800°C. The characterization of the products has shown that the particle size and morphology are strongly dependent on the nature of the phosphazene, the phosphazene/AuCl(PPh3) molar ratio and on the preparation methodology. Gold nanoparticles (NPs) with mean sizes as small as 3.5 nm were obtained from a [NP(O2C12H8)]n/ AuCl(PPh3) 1:1 film. The particle morphology was also strongly dependent on the experimentally conditions of the pyrolysis.

Solution and surfactant-free growth of supported high index facet SERS active nanoparticles of rhenium by phase demixing

“…A stable solid matrix forms 36 which is not lost as a volatile in the rst stage of annealing. During this carbonization process, some carbon monoxide 37 is also produced which eventually reduces the perrhenate ions to Re, which has a relatively low standard reduction potential of 0.300 V. 29 As the material solidies, the instability cause by decomposition processes in the host never fully develops and the layer is essentially a 'frozen-in' porous matrix [38][39][40] in which Re association occurs to ripen into high index NPs, without needing electrochemical surface reconstruction, 41 growth rate-altering surfactants, or co-reduction of species. 42,43 The holes in the solid support act as a nucleation point for the coalescence 35 (see ESI, Fig.…”