Surfactant-Mediated Resistance to Surface Oxidation in MnO Nanostructures
| Autor: | Bharati Debnath, S. M. Shivaprasad, Sayan Bhattacharyya, H. G. Salunke |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Nanostructure Rietveld refinement General Chemical Engineering Nanotechnology 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Article 0104 chemical sciences lcsh:Chemistry chemistry.chemical_compound lcsh:QD1-999 X-ray photoelectron spectroscopy Pulmonary surfactant Octahedron chemistry Chemical engineering Ferrimagnetism Surface layer 0210 nano-technology Trioctylphosphine oxide |
| Zdroj: | ACS Omega ACS Omega, Vol 2, Iss 6, Pp 3028-3035 (2017) |
| ISSN: | 2470-1343 |
| Popis: | The intrinsic physical properties of nanostructures of metals and their oxides are altered when they are prone to surface oxidation in ambient atmosphere. To overcome this limitation, novel synthesis methodologies are required. In this study, solid octahedral shapes of MnO limit the inward oxygen diffusion compared to that of the MnO-nanoparticle-assembled octahedra. In addition to morphology control, which restricts the thickness of the Mn3O4 surface layer, the binding chemistry of the surfactants plays an essential role. For example, the Mn3O4 surface layer is 0.4 nm thinner with trioctylphosphine oxide than with trioctylamine as the surfactant. The nanostructures were prepared by varying the surfactants, surfactant-to-precursor molar ratio, accelerating agent, and reaction heating rate. The surface oxidation of MnO nano-octahedra was probed by Rietveld analysis of X-ray diffraction patterns and X-ray photoelectron spectroscopy and characterized by magnetic measurements, as the presence of ferrimagnetic Mn3O4 shell on the antiferromagnetic MnO core provides an exchange coupling at the core–shell interface. Thicker the Mn3O4 shell, higher is the exchange-biased hysteresis loop shift. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|