I missed this one in my previous overview of Chem. Mater. Some nice zinc and titanium spectra courtesy of Brad Chmelka.
Chem. Mater., 18 (26), 6345 -6351, 2006. 10.1021/cm0621693 S0897-4756(06)02169-7 Web
Hierarchically Porous Rutile Titania: Harnessing Spontaneous Compositional Change in Mixed-Metal Oxides
Eric S. Toberer, Jan D. Epping, Bradley F. Chmelka,* and Ram Seshadri*
Materials Department and Materials Research Laboratory and Department of Chemical Engineering, University of California, Santa Barbara, California 93106
Abstract: In numerous applications involving fluid flow through a porous structure, performance improvements, such as better flow characteristics and increased fluid-solid contact, are obtained when multiple length scales of porosity are present in the porous medium. To this end, we have developed a route to hierarchically porous rutile titania that obviates the need for preformed or preassembled structure-directing agents. The preparation involves the successive leaching of phases and components from a dense composite of wurtzite ZnO and inverse spinel Zn2TiO4. The resulting monoliths are composed of grains of highly crystalline rutile titania and possess a hierarchy of interconnected pores with length scales of 5 m and 100 nm. Ex situ solid-state 67Zn and 47,49Ti NMR has helped probe local environments around these elements in both the mixed and pure crystalline materials that are formed during the leaching processes.
Thursday, April 05, 2007
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