Gold and gold-copper nanoparticles in 2-propanol: A radiation chemical study

The studies on the reduction of Au3+ to gold nanoparticles in presence and absence of Cu2+ under deoxygenated conditions in 2-propanol by radiolytic method have been carried out. On gamma-radiolysis, preliminary yellow colored solution of Au3+ changed to purple color owing to gold nanoparticles formation, which exhibits an absorption peak at around 540 nm. In the presence of Cu2+, absorption of gold-copper nanoparticles, which was also produced during gamma-radiolysis, was red shifted in contrast to the system containing no Cu2+. Under DLS studies the sizes of gold nanoparticles in the absence and the presence of Cu2+ were found to be larger (> 400 nm). However, in presence of polyethylene glycol, a stabilizer the nanoparticle sizes became smaller, sizes measured for gold and gold-copper nanoparticles are 40 and 140 nm, respectively. Moreover, the change in UV-vis spectra in the Cu2+ and Au3+ mixed system highlights the formation of gold-copper nanoparticles in core-shell type arrangement. (C) 2011 Elsevier Ltd. All rights reserved.