Selective hydrogenation of alkenes using ZIF-67 shell membrane deposited on platinum/alumina core catalyst

Abstract

Abstract A new core–shell catalyst (Pt/Al2O3@ZIF-67) for selective hydrogenation of alkenes was prepared by coating platinum/alumina (Pt/Al2O3) core with ZIF-67 shell membrane. The aperture size of the ZIF-67 (0.34 nm) is sufficiently small thus exclude large reactant and toxic substances thereby preventing deactivation and leakage of noble metal (Pt) incorporated in the core. The Pt/Al2O3@ZIF-67 core−shell catalyst exhibited exceptional size-selective catalytic properties in hydrogenation reaction. The core-shell catalyst is selective toward alkenes (hexene 0.17 nm, cyclohexene 0.42 nm, cyclooctene 0.55 nm), and showed excellent resistance to sulfur poisoning. The Pt/Al2O3@ZIF-67 core−shell catalyst displayed outstanding stability and maintain high activity and selectivity after four subsequent working cycles. The conversion of hexene reached 100% at 200 °C, while the conversion of cyclohexene and cyclooctene was 40% and 10%, respectively.