Dissolution of Au nanoparticles in hydrochloric acid solution as studied by optical absorption

Nanoscale Au particles dispersed in pores in mesoporous silica were prepared by the sol-gel technique, followed by thermal reduction in hydrogen. In contrast to bulk gold metal, An nanoparticles as so-called microelectrodes can be dissolved in hydrochloric acid (HCl), as measured by optical absorption. We attribute this dissolution phenomenon to the high chemical activity of nano-sized particles. (C) 2000 Elsevier Science B.V. All rights reserved.