Tailored Design of Mesoporous Metal Organic Framework Single Crystals by Kinetics‐Mediated Micelle Assembly for Efficient Asymmetrical Single‐Atom Catalysis

Abstract

AbstractConstructing mesoporous metal organic frameworks (MesoMOFs) with customizable meso‐ and micro‐environment is pivotal for asymmetric single‐atom catalysis, yet it is impeded by the strong self‐growth tendency of MOFs. In this work, a novel kinetics‐mediated micelle assembly strategy is introduced to realize the general fabrication of mesoporous zeolitic imidazolate framework (ZIF) single crystals. Spectroscopic characterizations and cryo‐electron cryomicroscopy reveal that the strategic use of water accelerates the MOFs kinetics‐mediated micelle assembly via enhancing ligand deprotonation, which suppresses the MOFs self‐growth, facilitating the cooperative assembly of micelles and MOFs. Furthermore, the water amount can modulate the Flory‐Huggins interaction parameters between the solvents and micelles, thereby precisely controlling the pore architectures from spherical, cylindrical to vesicular. Such versatile synthesis creates a new class of mesoporous asymmetric CoN3O single‐atom catalyst. Synchrotron spectral characterizations and theoretical calculations uncover that this asymmetric geometry localizes more electrons around Co center and upshift the d‐band center, stabilizing O* intermediates and promoting the oxygen reduction reaction (ORR). Consequently, the asymmetric mesoporous catalyst exhibits a half‐wave potential (0.91 V in alkaline media) and a high power density (185 mW cm−2) in a zinc‐air battery. This work provides a new approach for designing MesoMOFs for asymmetric single‐atom catalysis.