Hollow Mesoporous Metal–Organic Frameworks with Enhanced Diffusion for Highly Efficient Catalysis
Yongji Qin, Xu Han, Yaping Li, Aijuan Han, Wenxian Liu, Haijun Xu, Junfeng Liu
Abstract
Metal–organic frameworks (MOFs) with uniform porous structures show great promise for size/shape-selective catalysis, but their microsized pores and narrow channels inherently limit the diffusion of catalytic substrates and their catalytic efficiency. Herein, we report the fabrication of a hollow mesoporous MOF with hollow macroporous core and mesoporous shell, featuring a hierarchical porous structure that allows fast diffusion of reactants. The hollow core and mesoporous shell of the MOF were achieved by an elaborate design of a bimetallic MOF with stability differences in both metal–ligand bonds and spatial distribution via a boosted nucleation process, followed by selective etching treatment. Impressively, the hollow mesoporous MOF greatly enhanced the mass diffusion within the framework, which is demonstrated by the diffusion experiments, the molecular dynamics simulation, and the catalytic reaction by using 4-chlorostyrene as a probe. In addition, the as-prepared hollow mesoporous MOF exhibited superior catalytic performance when utilized as a Pd nanoparticles carrier, compared with solid Pd/MOF and commercial Pd/C catalysts toward benzyl alcohol oxidation.