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 γ-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 γ-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.

► Present radiation chemical study highlights high reactivity of Au2+ with Cu2+. ► Absorption of gold–copper nanoparticles is blue shifted as compared to copper nanoparticles. ► Change in UV–vis spectra with dose emphasizes core–shell type arrangement of Au–Cu nanoparticles.