RT Journal Article
T1 Cobalt (II) environment characterization in sol-gel thermochromic sensors
A1 Carmona Tejero, Noemí
A1 Bouzas, V.
A1 Jiménez, F.
A1 Plaza, M.
A1 Pérez García, Lucas
A1 García, M. A.
A1 Villegas, M. A.
A1 LLopis, J.
AB Optical absorption and magnetic properties of silica sol-gel monoliths doped with cobalt starting from different precursors and water/1-propanol molar ratios are investigated. Structural characterization of the sol-gel by X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy corroborate, that oxidising state of cobalt is Co^(2+). Furthermore, the Co^(2+) first neighbors are O atoms displaying a temperature transition from octahedral to tetrahedral coordination. The doped monoliths show thermochromic sensor activity ranging from 10 to 50⁰ C, which is related to the environment of Co^(2+) ions. The magnetic susceptibility also varies with Co^(2+) ions environment due to changes in the orbital contribution to the magnetic moment. Thus, we achieve a better understanding about environment of the Co^(2+) ions in the gel matrix and explain their       reversible temperature behaviour in spite of the rigid state of the host matrix.
PB Elsevier Science S A
SN 0925-4005
YR 2010
FD 2010-03-04
LK https://hdl.handle.net/20.500.14352/42771
UL https://hdl.handle.net/20.500.14352/42771
LA eng
NO ©2009 Elsevier B.V. All rights reserved.Authors wish to thank XAFS Beamline BM25 (Spanish-SPLine CRG) at the European Synchrotron Radiation Facilities, ESRF (Grenoble, France). The funding of the EU project “BONSAI” LSHB-CT-2006-037639. NC acknowledges the financial support of the FSE-MEC, Ramón y Cajal program ref. RYC-2007-01715.
NO EU project “BONSAI”
NO FSE-MEC, Ramón y Cajal program
DS Docta Complutense
RD 8 abr 2025