Anti-poisoning core–shell metal/ZIF-8 catalyst for selective alkene hydrogenation

• A synthesis method for a core–shell metal/ZIF-8 composite is reported.
• The core–shell Pd/ZIF-8 catalyst exhibits high selectivity in alkene hydrogenation.
• The ZIF-8 shell can protect the metal catalyst core from poisoning by thiophene.
• The proposed core/shell design is suitable for industrial hydrogenation catalysts.

We report a synthesis strategy for preparing a core–shell zeolitic imidazolate framework-8 (ZIF-8)-supported metal (gold or palladium) composite with catalytic selectivity and anti-poisoning properties. The catalytic performance of this ZIF-8/metal/ZIF-8 composite was investigated in catalytic alkene hydrogenation. The prepared ZIF-8/Pd/ZIF-8 composites exhibited high catalytic selectivity for 1-hexene over cis-cyclooctene and effectively protected the Pd particles from poisoning by thiophene during hydrogenation. The spent catalyst was almost fully regenerated after removing the adsorbed sulfur impurities. The reported core–shell catalyst design could be applicable to reactions in which the reactants to be processed contain components that could potentially poison the active sites.

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