Control of micropore size in supermicroporous titania-chromia system TiO2-Cr2O3

Sol-gel hydrolysis reactions of titanium(IV) isopropoxide and chromium (III) acetate hydroxide in the presence or absence of propanol, using the following amines as structure directing agents; N-hexylamine, N-methylhexylamine, and N-propylbutylamine, yielded microporous mixed metal oxides with the presence of pores largely in the 10-20 angstrom region, and surface areas that vary from 564 m(2)/g when N-hexylamine is employed as pore directing template to 494 m2/g when N-propylbutyl amine is employed as template. The maxima in pore size distribution increases with increase in steric crowding around the nitrogen in the alkyl amine. In addition, the nitrogen adsorption-desorption isotherm shifted from Type 1 isotherm when N-hexylamine is used as templating agent to Type 4 isotherm in N-propylbutylamine. (C) 2006 Elsevier B.V. All rights reserved.