Influence of sulfide ions on the formation and properties of gold nanoparticles in aqueous solutions

Abstract

The influence of sulfide ions on the formation of gold nanoparticles during reduction of HAuCl4 in an aqueous solution is studied using plasmon resonance spectroscopy and scanning tunneling microscopy. Upon the simultaneous addition of sodium citrate and sodium sulfide and for the molar ratios S/Au < 1, the nanoparticles have smaller sizes than those formed during the reduction only with sodium citrate under the same conditions; however, an increase in the sulfur content leads to an increase in the particle size. The gold nanoparticles are also obtained under microwave heating with a single-stage reaction of an AuCl4− aqueous solution with sodium sulfide. The particle size decreases with an increase in the S/Au ratio.