On the Rehydration of Organic Layered Double Hydroxides to form Low-Ordered Carbon/LDH Nanocomposites

Inorganics

Maria Pia Riccardi¹  Diego Antonioli²  Enrico Boccaleri²  Luca Palin²  Valentina Gianotti²  Eleonora Conterosito²  Maurizio Aceto²  Marco Milanesio² 

[1] Department of Earth and Environmental Sciences, University of Pavia, Via Ferrata 7, 27100 Pavia, Italy;Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale ‘‘A. Avogadro’’ (Italy), Via Michel 11, I-15121 Alessandria, Italy;

关键词: layered double hydroxides;    graphene;    graphite;    low ordered carbon;    mixed oxides;    rehydration;    memory effect;    X-ray diffraction;    Raman spectroscopy;    scanning electron microscopy;   

DOI  :  10.3390/inorganics6030079

来源: DOAJ

【 摘 要 】

Low-ordered carbon/layered double hydroxide (LDH) nanocomposites were prepared by rehydration of the oxides produced by calcination of an organic LDH. While the memory effect is a widely recognized effect on oxides produced by inorganic LDH, it is unprecedented from the calcination/rehydration of organic ones. Different temperatures (400, 600, and 1100 °C) were tested on the basis of thermogravimetric data. Water, instead of a carbonate solution, was used for the rehydration, with CO2 available from water itself and/or air to induce a slower process with an easier and better intercalation of the carbonaceous species. The samples were characterized by X-ray powder diffraction (XRPD), infrared in reflection mode (IR), and Raman spectroscopies and scanning electron microscopy (SEM). XRPD indicated the presence of carbonate LDH, and of residuals of unreacted oxides. IR confirmed that the prevailing anion is carbonate, coming from the water used for the rehydration and/or air. Raman data indicated the presence of low-ordered carbonaceous species moieties and SEM and XRPD the absence of separated bulky graphitic sheets, suggesting an intimate mixing of the low ordered carbonaceous phase with reconstructed LDH. Organic LDH gave better memory effect after calcination at 400 °C. Conversely, the carbonaceous species are observed after rehydration of the sample calcined at 600 °C with a reduced memory effect, demonstrating the interference of the carbonaceous phase with LDH reconstruction and the bonding with LDH layers to form a low-ordered carbon/LDH nanocomposite.

【 授权许可】

Unknown