Mesoporous Mo-SiO2 and SiO2 synthesized by sol-gel method were impregnated with Pt precursor in order to obtain Pt/Mo-SiO2 and Pt/SiO2 catalysts. The catalysts were tested in cyclohexane (CH) and methylcyclohexane (MCH) dehydrogenation reaction and characterized using different techniques. For MCH dehydrogenation, the catalysts' specific initial activity followed the trend: Pt/Mo-SiO2 > Mo-SiO2 > Pt/SiO2. The synergy effect between Pt and Mo did not occur due to the large contribution of acidity of partially reduced Mo-SiO2 sample to its catalytic response and to the absence of H-2 spillover for Pt/Mo-SiO2. Unlike MCH dehydrogenation, the synergy between Pt and Mo was observed for CH dehydrogenation over Pt/Mo-SiO2 catalyst. For both Pt/SiO2 and Pt/Mo-SiO2, the catalyst bifunctionality (metal and acid functions) and the H-2 spillover effect were more important for catalyst behavior in CH dehydrogenation than in MCH dehydrogenation. (C) 2018 Elsevier B.V. All rights reserved.