Selective Synthesis Of Different-Sized Gold Nanoclusters Through Hci-Etching And -Growth Effect

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 Au-7 and Au-13 clusters through adding HCl to the traditional Au-11 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.