Electrochemical formation and characterization of copper oxygenous compounds in alumina template from ethanolamine solutions

Peculiarities of Cu, Cu(OH)2, Cu2O, and CuO a.c. deposition into the porous alumina template from various triethanolamine (TEA) solutions were studied using anodic stripping, Fourier transform infrared (FTIR), XRD and Raman spectroscopy. Copper deposition into the porous alumina template mainly in the metallic form and, as a consequence, coloring them in cherry tints was found only from the acid solutions. The Raman vibrational spectrum of porous alumina a.c. treated in weakly acidic Cu(II)–TEA solutions (pH 4.1–5.3) and colored in greenish tint was found to be consisted of two main peaks located at 519–522 and 613–619 cm−1 what is characteristic of Cu2O lattice vibrations. The additional peak located at about 365 cm−1 was detected in the spectrum of alumina colored in gray, obtained from neutral to alkaline solutions, what is indicative of CuO codeposition with Cu2O. These results were confirmed by FTIR and X-ray absorption spectra clearly discernible absorption peaks of Cu2O, CuO, and Cu(OH)2 depending on the composition of Cu(II)–TEA solution used.