Carbon black (CB)-supported Pt metal nano-particles were covered with microporous silica layers using successive hydrolysis of 3-aminopropyl-triethoxysilane (APTES) and methyltriethoxysilane (MTES). 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 H-2 atmosphere as compared with Pt/CB. As a result, this catalyst showed higher catalytic activity for cyclohexane decomposition than Pt/CB after thermal treatment.