Molecular sieve driven selectivity using encapsulated Pt nanoparticle in single crystal zeolite
Résumé
Carbon monoxide separation from light hydrocarbon is difficult, especially with methane and olefins. The selective oxidation of carbon monoxide to CO2 at high conversion level is an attractive solution since CO2 removal technologies show better performances. The challenge is to prevent the conversion of hydrocarbons while the CO oxidation proceeds. Therefore the development of a highly selective catalyst is necessary. Pt@silicalite 1 yolk-shell material with a monocrystalline zeolitic shell was prepared1. A single Pt nanoparticle is encapsulated in each hollow ultrathin silicalite-1 shell which can act as a molecular sieving membrane (Fig. 1a). The CO oxidation in the presence of propylene was performed with Pt@Silicalite 1 and compared to the reference Pt/SiO2. With the latter, the CO conversion significantly drops in the presence of propylene due to strong poisoning of Pt site by CO. On Pt@silicalite 1, we show that full conversion of CO is achieved while propylene is not oxidized (Fig. 1b). Although CO and propylene can in principle diffuse through the silicalite-1 shell, we will show that selectivity of the reaction is governed by the transport properties through the zeolite shell.