Synthesis of new Sn incorporated layered double hydroxides and their evolution to mixed oxides

A new series of (MgAlSnIV)-Al-II-Sn-III hydrotalcite (HT)-like layered doub le hydroxides (LDHs) with Mg/Al/Sn = 3:1:0 to 3:0:1 were synthesized for th e first time by a simple coprecipitation method at room temperature. The in corporation of Sn4+ in the HT-like layer was investigated by powder X-ray d iffraction (PXRD), chemical analysis, simultaneous thermogravimetric/differ ential thermal analysis (TG/DTA), and N-2 adsorption-desorption experiments . A single phase corresponding to LDH could be obtained in the composition range Mg/Al/Sn = 3:1:0 to 3:0.7:0.3. Above this composition, in addition to LDH, a MgSn(OH)(6) phase was formed. Thermal calcination of these MgAlSn-L DHs at 45 degrees C resulted in the formation of MgO solid solutions in whi ch both Al3+ and Sn4+ were dissolved. The surface area and pore volume decr eased with increasing Sn content for as-synthesized as well as for calcined samples. Calcination at 1100 degrees C offered a well-crystallized phase c orresponding to Mg2SnO4 "inverse spinel" in addition to the less crystallin e MgO and MgAl2O4 phases. (C) 2000 Elsevier Science Ltd.