Hydrothermal preparation and anion exchange of Co2+–Ni2+–Fe3+ CO32− LDHs materials with well regular shape

Fe3+-based Co2+–Ni2+–Fe3+ CO32− LDHs materials with well regular shape were hydrothermally synthesized by urea as hydrolysis agent and trisodium citrate (TSC) as a chelating agent at 150 °C. The obtained hexagonal platelets had a mean lateral size of about 800 nm and a thickness of 30 nm. A layered structure transform process due to the symmetric transform of carbonate anions in the interlayer was observed. The as-prepared Co2+–Ni2+–Fe3+ CO32− LDHs material was completely converted to Cl−-LDHs material by treating with a NaCl–HCl mixed solution, retaining its regular shape. LDHs materials intercalated with a variety of anions (such as NO3−, ClO4−, and dodecyl sulfate) were further prepared from Cl−-LDHs material via an anion-exchange process employing corresponding salts.