Block copolymer-assisted synthesis of mesoporous, multicomponent oxides bynonhydrolytic, thermolytic decomposition of molecular precursors in nonpolar media

A general route for the synthesis of homogeneous mixed-element oxides, base d on the use of block polyalkylene oxide copolymers and single-source molec ular precursors, is described. Thermolytic decomposition of the molecular p recursors in the presence of an anhydrous solution of the block copolymer ( in toluene) led to monolithic gels. The polymeric structure-directing agent was then removed by calcination at 500 degreesC for 3 h under O-2. The gen erality of this synthetic approach is demonstrated with the molecular precu rsors Zr[OSi((OBu)-Bu-t)(3)](4), (EtO)(2)Ta[OSi((OBu)-Bu-t)(3)](3), Fe[OSi( (OBu)-Bu-t)(3)](3). THF and [Al((OPr)-Pr-i)(2)O2P((OBU)-B-t)(2)](4), which have been converted to the corresponding mesostructured materials ZrO2-4SiO (2), Ta2O5-6SiO(2), Fe2O3. 6SiO(2), and AlPO4 (denoted UCB1-ZrSi, UCB1-TaSi , UCB1-FeSi, and UCB1-AlP, respectively). These mesostructured materials, c haracterized by TEM, XRD, N-2 porosimetry, EDX, and NMR spectroscopy, exhib it wormholelike pore structures, high surface areas, and narrow pore size d istributions.