Selective CO oxidation over carbon-coated Pt/SiO2-TiO2 particles

Carbon-coated Pt/SiO2-TiO2 catalyst was synthesized by vapor infiltration of furfuryl alcohol into porous SiO2-TiO2 particles, followed by carbonization at 1000 °C under N2 atmosphere. At the elevated temperature of 1000 °C, the Pt particles on the uncoated SiO2-TiO2 particles aggregated and the micropores and macropores of the uncoated SiO2-TiO2 particles disappeared. Further, a phase transformation of TiO2 from anatase to rutile was complete at 1000 °C. On the other hand, the aggregation of Pt and SiO2-TiO2 particles and the phase transformation of TiO2 were partly suppressed for the carbon-coated Pt/SiO2-TiO2 particles. The carbon-coated catalyst showed a high activity and high selectivity for CO oxidation in excess H2, due to selective adsorption and diffusion of CO through the carbon layer. This work demonstrates that reactant selectivities (CO/H2) in oxidation can be enhanced by a combination of catalyst particles with an adsorption-selective layer.