Intercalation, exfoliation, and reduction of VOPO4 center dot 2H(2)O were conducted in 2-butanol alone and in a mixed-alcohol solvent (2-butanol and ethanol). Whereas both processes produced crystallites of pure VOHPO4 center dot 0.5H(2)O, much smaller and thinner crystallites (average size, 340 x 35 nm) were formed in the mixed alcohol compared with 2-butanol alone (average size 950 x 200 nm). The small, thin crystallites of precursor VOHPO4 center dot 0.5H(2)O could be transformed into sharply angular nanosized crystallites (60 nm long and 31 nm thick) of highly crystalline (VO)(2)P2O7, without mesopores. When used as a catalyst, this compound exhibited higher activity and selectivity to maleic anhydride (75% at 80% conversion) for selective oxidation of n-butane compared with that derived from the precursor prepared in 2-butanol alone. The high activity of the nanosized crystallites of (VO)(2)P2O7 is attributed to their large surface area (40 m(2) 9(-1)), which is due to their smaller dimensions, and their high selectivity may be attributed to the lack of mesopores as well as their highly crystalline state. (c) 2007 Elsevier Inc. All rights reserved.