Mesoporous Ta Oxide. 2. Improvement of the Synthetic Method and Observation of Mesostructure Formation

The ligand-assisted templating method for the production of mesoporous Ta 2 O 5 was improved by the removal of noncoordinating alkylamine surfactant before aging. The improved method increased the uniformity of the porous structure and the particle size. The immediate precipitation after the hydrolysis of the alkylamine-coordinated Ta(OEt) 5 allowed the detailed observation of the powder particles at each synthesis step by XRD, N 2 adsorption isotherms, SEM, and TEM. TEM and XRD observations found that micelle rods already existed in particles formed soon after hydrolysis. Therefore, micelle rods were suggested to be formed even in the absence of water. Final aging at 453 K encouraged the arrangement of the mesopores in a wormhole-like structure, which was evidenced by the type H2 hysteresis loop of the desorption branch of N 2 adsorption−desorption isotherms in addition to TEM images.