Synthesis of Atomically Dispersed Nickel Confined in Hierarchical MFI Zeolite.

Mesoporous zeolite-anchored atomically dispersed metal (ADM) catalysts are capable of overcoming diffusion limitations, promoting mass transfer, and exposing more active sites. These features make them one of the most ideal heterogeneous catalysts. However, introducing both mesoporosity and ADM species into zeolite structures while avoiding metal clustering remains a significant challenge. Herein, we report the hierarchical MFI zeolite encapsulated atomically dispersed nickel species using a ligand-protected in situ synthesis strategy with a tri-functional template. This template incorporates quaternary ammonium hydrophilic head groups linked to central metal-coordinated porphyrins by alkyl chains, which guide the formation of mesoporous MFI zeolite structure while simultaneously suppressing nickel clustering. The resulting catalyst exhibits a hierarchical architecture comprising MFI nanosheets with enhanced 90° rotational intergrowth, and the dispersed Ni sites are evenly distributed within the zeolite framework. The catalyst exhibited a high activity and efficient utilization of Ni in probing CO₂ hydrogenation reaction. The use of functionalized metal-coordinated porphyrins as a structure-directing agent to generate zeolite-supported metal catalysts is transferable, which opens new possibilities for controlling zeolite architecture.