Synthesis of Homogeneous Manganese-Doped Titanium Oxide Nanotubes from Titanate Precursors

• Published in: Journal of physical chemistry. C Vol. 117; no. 1; pp. 697 - 702
• Main Authors: Szirmai, Péter, Horváth, Endre, Náfrádi, Bálint, Micković, Zlatko, Smajda, Rita, Djokić, Dejan M, Schenk, Kurt, Forró, László, Magrez, Arnaud
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 10-01-2013
• Subjects: Applied sciences; Chemical synthesis methods; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Methods of nanofabrication; Molecular electronics, nanoelectronics; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanotubes; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Structure of solids and liquids; crystallography; Cubic lattices; Doping; Nanotubes; Long-range order; Titanates; Manganese additions; Precursor; Heat treatments; Manganese oxides; SQUID devices; Magnetometry; Hydrothermal synthesis; Experimental design; Electron paramagnetic resonance; Ion exchange; Titanium oxide; Nanomaterial synthesis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp3104722

We report a novel synthesis route of homogeneously manganese-doped TiO2 nanotubes in a broad concentration range. The scroll-type trititanate (H2Ti3O7) nanotubes prepared by hydrothermal synthesis were used as precursors. Mn2+ ions were introduced by an ion exchange method resulting Mn x H2–x Ti3O7. In a subsequent heat treatment, they were transformed into Mn y Ti1–y O2, where y = x/(3 + x). The state and the local environment of the Mn2+ ions in the precursor and final products were studied by the electron spin resonance (ESR) technique. It was found that the Mn2+ ions occupy two positions: the first having an almost perfect cubic symmetry while the other is in a strongly distorted octahedral site. The ratio of the two Mn2+ sites is independent of the doping level and amounts to 15:85 in Mn x H2–x Ti3O7 and to 5:95 in Mn y Ti1–y O2. SQUID magnetometry does not show long-range magnetic order in the homogeneously Mn2+-doped nanotubes.