Monofunctional hybrid materials based on Keggin-type heteropolyacids supported on mesostructured silica were used in isomerization of n-hexane. The heteropolyacids, namely H-3 PW12O40 or H4SiW12O40, were immobilized onto SBA-15 type silica by incipient wetness impregnation. The resulting catalysts were thoroughly characterized by N-2 adsorption-desorption isotherms, XRD, P-31 NMR, TGA and FT-IR. These hybrid materials were active for the gas-phase isomerization of n-hexane. Various reaction parameters and catalyst features were investigated: tungsten loading, reaction temperature, contact time, pressure and nature of the polyanion. All results could be explained by a competition of the mono- and bimolecular mechanisms. Supported tungstosilicic acid was intrinsically more selective than phosphotungstic counterpart and should be preferred for applications in isomerization of alkanes. A deactivation of the catalysts was observed due to the poisoning of acid sites by coke formation. (C) 2014 Elsevier B.V. All rights reserved.