Stabilization of Co2+ in layered double hydroxides (LDHs) by microwave-assisted ageing

Co-containing layered double hydroxides at different pH have been prepared, and aged following different routes. The solids prepared have been characterized by element chemical analysis, powder X-ray diffraction, thermogravimetric and differential thermal analyses (both in nitrogen and in oxygen), FT-IR and Vis–UV spectroscopies, temperature-programmed reduction and surface area assessment by nitrogen adsorption at −196 °C. The best conditions found to preserve the cobalt species in the divalent oxidation state are preparing the samples at controlled pH, and then submit them to ageing under microwave irradiation.

The use of microwave-hydrothermal treatment, controlling both temperature and ageing time, permits to synthesize well-crystallized nanomaterials with controlled surface properties. An enhancement in the crystallinity degree and an increase in the particle size are observed when the irradiation time is prolonged.Figure optionsDownload as PowerPoint slide