Effect of Pt-MOx (M = Fe, Co) interaction on the preferential oxidation of CO over Pt/MOx/TiO2 catalysts prepared by selective electrostatic adsorption

Abstract

In this work, the catalytic properties of Pt/MOx/TiO2 (M = Fe, Co) catalysts prepared by strong electrostatic adsorption (SEA), were investigated for the preferential oxidation (PROX) of CO in H2. The SEA method was chosen to achieve a preferential adsorption of Pt onto supported MOx nanoparticles rather than onto the TiO2 surface. XPS, TPR and TEM analysis indicate that the enhancement in the catalytic activity of Pt/MOx/TiO2 is related to a synergetic effect originated by a close contact between Pt and MOx (M = Fe, Co) surface. The results clearly show that Pt supported on CoOx/TiO2 calcined at 300 °C, and then reduced at 100 °C, exhibits the highest activity, e.g. higher CO conversion and CO2 selectivity, among the supported catalysts studied in this work, that was attributed to a higher concentration of Pt-CoOx moieties over the catalytic surface. This study reports a simple and efficient way to synthesize Pt-promoted catalysts where strong metal-support interactions are highly desired to improve the catalytic performance of selective oxidation reactions.