Synthesis of CTAB–IPA reduced copper nanoparticles

Synthesis of copper nanoparticles by reduction of Cu2+ ions to Cu0 in the presence of cetyltrimethylammonium bromide (CTAB) and isopropanol (IPA). Experiments included the synthesis of copper nanoparticles by varying the molar concentration of CTAB keeping that of Cu2+ ions constant. In the first set Cu2+-IPA solution was added to CTAB–IPA mixture, the sequence was reversed in the second set. Differences in results are observed in each case. UV–visible spectra were recorded to note the changes taking place as a function of the added volume. Plasmon band for Cu0 at ∼560 nm and oligomers of Cu0 at ∼290 and ∼340 nm wavelengths are observed. CTAB appears to play the role of catalyst in the reduction of Cu2+ ions in IPA under ambient conditions. Transmission electron microscopic (TEM) analysis of the copper nanoparticles synthesized at the two extreme molar ratios of Cu2+:CTAB, i.e. 1:0.25 and 1:30 show particles of size ∼5–20 and ∼2–10 nm, respectively, with a spherical morphology.