Home > Articles > Published articles > Nanocasting synthesis of mesoporous SnO₂ with a tunable ferromagnetic response through Ni loading |
Date: | 2016 |
Abstract: | Undoped and Ni-doped ordered mesoporous SnO₂ powders ([Ni(II)]/[Sn(II)] = 0 : 100, 5 : 95, 15 : 85, 20 : 80) were synthesized by nanocasting from mesoporous KIT-6 silica. The resulting Ni content in the Ni-loaded powders ranged between 1 at% and 9 at%. Successful replication of the silica template was verified by scanning electron microscopies for all samples. Residual silicon content did not surpass 4 at%. X-ray diffraction analyses showed that the powders were nanocrystalline, being the rutile-like phase of SnO₂ the dominant structure. Changes in the lattice constants depending on the Ni content were observed, suggesting that Ni enters the rutile structure of SnO₂ to some extent. No extra phases attributed to Ni were detected in the powders except for the sample synthesized from 20 : 80 [Ni(II)]/[Sn(II)], for which NiO as secondary phase was observed. The oxidation state and spatial distribution of Ni in the powders was investigated by X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) measurements, respectively. For 6 at% and 9 at% Ni content, the presence of Ni2+ was established. The corresponding EELS mapping showed that a fraction of Ni (the one not forming part of the rutile phase) tended to accumulate at the pore edges, forming a nanometer-thick NiO layer. Compared to undoped SnO₂, Ni-containing powders exhibit a ferromagnetic response at low and room temperatures. Uncompensated spins at the surface of NiO are likely to contribute, in part, to the observed ferromagnetic properties. |
Grants: | European Commission 648454 Ministerio de Economía y Competitividad MAT2014-57960-C3-1-R Ministerio de Economía y Competitividad RYC-2012-10839 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1015 |
Note: | Altres ajuts: China Scholarship Council (CSC)/201406220145 i China Scholarship Council (CSC)/201306250050 |
Rights: | Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. |
Language: | Anglès |
Document: | Article ; recerca ; Versió publicada |
Published in: | RSC advances, Vol. 6, Issue 106 (2016) , p. 104799-104807, ISSN 2046-2069 |
9 p, 2.2 MB |