Photochemical formation of silver and gold nanostructures at the air–water interface andtheir electrocatalytic properties

Abstract

In this paper, we report a simple method of fabricating silver and gold nanostructures atthe air–water interface, which can be spontaneously assembled through the reduction ofAgNO3 and HAuCl4 with ultraviolet (UV) irradiation in the presence of polyacrylic acid (PAA), respectively. Itwas found that the building blocks in the silver nanostructure are mainly interwoven silvernanofilaments, while those of the gold nanostructure are mainly different sizes ofgold nanoparticles and some truncated gold nanoplates, and even coalescenceinto networks. At the air–water interface, these silver and gold nanostructurescan be easily transferred onto the surface of indium tin oxide (ITO) slides andused for electrochemical measurements. After a replacement reaction withH2PdCl4, the silvernanostructure is transformed into a Ag–Pd bimetallic nanostructure, with good electrocatalytic activityfor O2 reduction. The gold nanostructure can also show high electrocatalyticactivity to the oxidation of nitric oxide (NO) with a detection limit of about10 µM NaNO2 atS/N = 3.