Synergistic Local Hydrogen Confinement and Spillover over Pd@ZIF-8-AT Enables Mild-Condition Hydrogenation of Dicyclopentadiene

Abstract

The hydrogenation of dicyclopentadiene (DCPD) to tetrahydrodicyclopentadiene (THDCPD) is a pivotal process for highenergy-density aviation fuels. However, achieving superior catalytic efficiency under mild conditions remains a formidable challenge due to the inherent difficulty in synchronizing hydrogen enrichment, activation, and migration at active sites.Herein, we report a sophisticated Pd@ZIF-8-AT catalyst designed to orchestrate synergistic local hydrogen confinement and enhanced hydrogen spillover. By incorporating 5-aminotetrazole (5-AT) into the ZIF-8 framework, we engineered a defectrich environment with abundant N-donor sites, which ensures the high dispersion of ultrasmall Pd nanoparticles within the nanoconfined voids. The synergy between the strong H2 affinity of Pd sites and the confined nanopockets of the ZIF-8-AT host creates a "local hydrogen pressurized zone," ensuring a continuous H-supply even at low bulk pressures.Simultaneously, the formation of Pd-N electronic bridges modulates the electronic configuration of Pd centers, which not only lowers the activation energy for H2 dissociation but also facilitates the interfacial hydrogen spillover onto the MOF support. Consequently, Pd@ZIF-8-AT achieves >99% conversion and selectivity for DCPD hydrogenation at room temperature and low pressure (30 °C, 1 MPa), significantly outperforming state-of-the-art catalysts. This work not only provides a molecular-level understanding of hydrogen dynamics within MOF-based nanoreactors but also sets a benchmark for designing highly efficient catalysts for mild-condition industrial hydrogenations.