Carbon-supported Pt metal nanoparticles covered with silica layer including phenyl or methyl groups were prepared using successive hydrolysis of 3-aminopropyl-triethoxysilane (APTES) and phenyltriethoxysilane (PhTES) or methyltriethoxysilane (MTES). The Pt catalyst covered with silica layers containing functional groups showed higher activity in the cyclohexane dehydrogenation, compared with Pt catalysts covered with a silica layer containing no functional groups, because the microporous structure of silica layers which wrapped Pt metal particles increased the diffusion capability of cyclohexane. The Pt/CB nanoparticles covered with microporous silica layers showed the high sintering resistance of Pt metal particles to thermal treatment at 973 K in a H2 atmosphere as compared with Pt/CB. As a result, this catalyst showed higher catalytic activity for cyclohexane dehydrogenation than Pt/CB after thermal treatment
