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, Au 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. q2000 Elsevier Science B.V. All rights reserved