The derivatographic and spectral (diffuse reflection) studies of cobalt and/or ZrO₂ and  promoted low-temperature mordenite catalysts of the n-butane to isoparaffins conversion prepared by various methods have been carried out. Samples obtained by solid-phase modification, possess the more expressed thermal effects in comparison with the impregnated ones. The cobalt localization places on the most active samples surface are detected by the spectral method