Selective Synthesis of Different-Sized Gold Nanoclusters through HCl-Etching and -Growth Effect

Abstract

Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 and Au13 clusters through adding HCl to the traditional Au11 synthetic route at different reaction time. Time-dependent mass spectra and UV-Vis spectra were employed to monitor these two HCl-directed processes, and revealed the distinct roles of HCl as an etchant or a growth promotor, respectively. Furthermore, parallel experiments on independent synthetic routes involving only non-chlorine H+ (acetic acid) or Cl− (tetraethy lammonium chloride) instead of HCl were performed, which illustrated the main role of H+-etching and Cl−-assisted growth in HCl-directed cluster synthetic routes. We propose the HCl-etching is mainly achieved via the H+ action to break the Au(I)-PPh3 part of clusters, while the HCl-promoted growth is realized via the attachment of Au-Cl species to the pre-formed clusters.