Conditions for the formation of copper nanoparticles by reduction of copper(II) ions with hydrazine hydrate solutions

Polyol-mediated synthesis of size-controlled copper nanoparticles under microwave irradiation

“…In agreement with color change of the solutions, UV-vis spectra affirm the d-d transition of the Cu(II) complex observed at the wavelength of 625 nm (blue solution) and then shifting to 576 nm attributed to surface plasmon resonance of Cu(0) nanoparticles (red colloidal suspension) ( Figure 2). This absorbance band also confirms the formation of spherical particles with the range of 2 to 10 nm in diameter [6]. Noticeably, in the absence of PVP, the only red precipitates were obtained, evidencing the necessity of an auxiliary stabilizer, PVP in this case, for the steric stabilization based on its bulky structure and weak binding to the metal surface [1].…”

“…Noticeably, in the absence of PVP, the only red precipitates were obtained, evidencing the necessity of an auxiliary stabilizer, PVP in this case, for the steric stabilization based on its bulky structure and weak binding to the metal surface [1]. (Figure 3) [6]. Besides, we did not detect any crystalline Cu(I) and Cu(II) phases, probably thanks to the reduced property of glycerol and thus protecting the re-oxidation of Cu(0) in the ambient atmosphere.…”

Oxidation of Copper Nanoparticles Protected with Different Coatings and Stored under Ambient Conditions

“…The Cu NPs obtained by methods 1 and 2 were characterized immediately after synthesis by XRD, TGA, and TEM techniques. The X-ray diffraction patterns for both Cu NPs synthesized methods exhibit three reflections located at 2θ = 43.4, 50.5, and 74.0°, attributed to the (111), (200), and (220) crystal planes, respectively, belonging to pure copper with face-centered cubic symmetry (FCC) [31,32] and corresponding to the diffraction pattern of metallic copper (JCPDS No. 04-0836) [33], as shown at the bottom of Figure 2.…”

Synthesis of Copper Nanoparticles Using Mixture of Allylamine and Polyallylamine

“…Reaction R5 that used AAm/Cu molar ratio of 43 suggests that it is possible to obtain copper nanoparticles without evidence of oxidation when the concentration of AAm in the reaction medium is not very high. Figure 6 shows the XRD diffractograms of nanoparticles synthetized under different AAm/PAAm molar ratios (Table 1) the graph readily identifies each type of NPs and only the diffractogram obtained in NPs R5 exhibits the three properties of metallic copper reflections [48,49]. XRD analysis indicated that the reaction conditions used in R5 allowed the preparation of Cu-NPs without the presence of impurities such as CuO, Cu 2 O, and Cu(OH) 2 .…”