Competitive coordination strategy for the synthesis of hierarchical-pore metal-organic framework nanostructures

Metal-organic frameworks (MOFs) usually have micropores smaller than 2 nm, which may restrict their applications in some cases. Hierarchical-pore MOFs (H-MOFs) are a new family of MOF materials, possessing both micro-and mesopores to address this problem. Here we demonstrate a competitive coordination strategy for the synthesis of H-MOF nanostructures, such as two-dimensional (2D) H-MOF nanosheets and H-MOF nanocubes, evolving through an etching process tuned by a competitive ligand. The as-synthesized 2D H-MOF nanosheets can serve as a substrate to in situ immobilize Pd nanoparticles to achieve a surfactant-free Pd catalyst, by means of a simple soaking method of Pd2+ precursors. Combined with the unique structure and gas adsorption capacity of H-MOF-5, the Pd-HMOF-5 catalyst exhibits superior catalytic performance.