A series of mesoporous vanadium nitrides with surface areas up to 60 m(2)/g was prepared via the temperature-programmed reaction of V2O5 with NH3, and evaluated for the dehydrogenation of n-butane, Thermogravimetric analysis coupled with X-ray diffraction and scanning electron microscopy indicated that the solid-state reaction proceeded by the sequential reduction of V2O5 (V2O5 --> V4O9 --> VO2 --> V2O3 --> VO0.9) and concluded with the topotactic substitution of nitrogen for oxygen in VO0.9, An experimental design was performed to determine effects of the heating rates and space velocities on the VN microstructures, The heating rates had minor effects on the surface areas and pore size distributions; however, increasing the space velocity significantly increased the surface area and decreased the average pore size, We believe the effect of the space velocity was due to inhibition of the gas-solid reactions by H2O and/or N-2. Temperature-programmed reduction and pretreatment studies indicated that the passivated VN could be activated by reduction in H-2 at 500 degrees C for 3 h, Lower reduction temperatures or times resulted in suppressed surface areas and O-2 chemisorptive uptakes. Oxygen chemisorption on the fully reduced vanadium nitrides scaled linearly with the surface area. The corresponding O/V-surface ratio was 0.56 suggesting that each oxygen atom chemisorbed to approximately two surface vanadium atoms. The vanadium nitrides were highly active butane dehydrogenation catalysts with selectivities in excess of 98%. Volumetric reaction rates for the highest surface area VN were superior to those for a Pt-Sn/Al2O3 catalyst. The average turnover frequency for the VN catalysts was 4.3 x 10(-4) s(-1) at 450 degrees C assuming that oxygen chemisorbed atomically onto the active sites. The corresponding turnover frequency for the PtSn/Al2O3 catalyst was 6.3 x 10(-2) s(-1) suggesting that while selectivities for the VN and Pt-based catalysts were similar, VN had a lower intrinsic activity.