SYNTHESIS AND CHARACTERIZATION OF ALUMINA-PILLARED LAYERED TETRATITANATES WITH DIFFERENT INTERLAYER SPACINGS

A series of alumina-pillared layered tetratitanates with different interlayer spacings (d(001) = 15.2-17.0 Angstrom) has been first prepared through a step-wise exchange process and by finely changing the exchange reaction conditions such as reaction time and molar ratio of reactants in the reaction mixture, and hydrolysis conditions such as the pH and aging time used to generate the pillaring agent. Apart from the interlayer spacing, the pore diameter and specific surface area of the pillared samples can also be changed by varying the preparation conditions. The resulting alumina-pillared layered tetratitanates were porous, with both micro- and meso-pores (average pore diameter=61.5-95.8 Angstrom). The specific surface area (BET, N-2, 77 K) of the starting material K2Ti4O9 (5 m(2) g(-1)) was increased by pillaring up to 56.6-105.6 m(2) g(-1). The relatively high surface area is mainly due to the microporous structure of the interlayered spaces formed by stable alumina pillars. The structure of the alumina-pillared layered tetratitanates was thermostable above 500 degrees C. The results are compared with those previously reported.