Naslov
Synthesis and long-term phase stability of Mn3O4 nanoparticles

Autori
Ristić, Mira ; Musić, Svetozar ; Popović, Stanko ; Dragčević, Đurđica ; Marciuš, Marijan ; Ivanda, Mile

Izvornik
Journal of molecular structure (0022-2860) 1044 (2013); 255-261

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
γ-MnOOH; FT-IR; Mn3O4; Raman; UV/Vis/NIR

Sažetak
The synthesis and long-term phase stability of hausmannite (Mn3O4) nanoparticles were investigated. The experimental techniques used were XRD, FT-IR, Raman, UV/Vis/NIR and FE-SEM. Mn3O4 nanoparticles were synthesized by (a) precipitation from Mn(NO3)2 and NH4OH solutions and ageing of suspensions obtained at 160 or 20 °C and (b) precipitation from MnCl2 solution with addition of H2O2 and NH4OH solutions and ageing of suspensions obtained at 90 or 20 °C. The order of adding H2O2 or NH4OH influenced the phase composition of the precipitate. A combination of XRD, Raman and FT-IR techniques was useful in investigating the long-term phase stability of Mn3O4 and changes in the nonstoichiometry of these particles. The IR bands recorded in the range 623-635 cm-1 can be assigned to the nonstoichiometry of these particles. It was shown that the IR bands at 1085, 1115 and 1150 cm-1 corresponding to OH- vibrations can be used in the interpretation of a very early stage of the phase transformation Mn3O4 → γ-MnOOH. The appearance of an IR band (shoulder) in FT-IR spectra in the range 594-599 cm-1 was discussed in terms of a possible presence of very fine γ-MnOOH particles in traces and restricted to the surface of Mn3O4 nanoparticles. The water (moisture) adsorbed on Mn3O4 particles plays a key role in the phase transformation Mn3O4 → γ-MnOOH. Other parameters related to the synthesis route also play a certain role in this phase transformation. UV/Vis spectra were briefly discussed.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

Napomena
Rad je prezentiran na skupu 31st European Congress on Molecular Spectroscopy "Molecular spectroscopy and molecular structure", održanom od 26.–31.08.2012.g., Cluj-Napoca, Rumunjska ; Simion Aştilean, Austin J. Barnes, Vasile Chiş, Onuc Cozar (ur.).

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