Preparation And Application Of Two-dimensional Zeolitic Imidazolate Framework-derived Materials

Metal-organic frameworks(MOFs)are a type of crystalline porous materials built by coordination interaction between metal nodes and organic ligands.Such materials have tuneable structure and function,large specific surface and large pore volume.Among them,two-dimensional MOF material not only retains the unique characteristics of the MOF material itself,but also introduces the advantages of the two-dimensional material.But the controllable preparation of two-dimensional MOF materials is still a challenge.Therefore,it is of great significance to prepare controllable two-dimensional MOF materials and their derivatives to explore the applications of these materials in the fields of catalysis and biomedicine.Herein,two-dimensional zeolite imidazolate frameworks(ZIFs)are chosen.These materials are zeolite-like MOF materials synthesized by the reaction of Zn(II)or Co(II)with imidazole-based ligands.On the basis of the two-dimensional leaf-like ZIF-L,we controlled and optimized the synthesis conditions,realized the controllable preparation,constructed the core-shell structure,and applied ZIF materials and their derivatives in the electrocatalytic oxygen reduction reaction,zinc-air battery and selective enrichment of glycopeptide.1.By introducing two-dimensional bimetallic NiCo-MOF nanosheets into the ZIF-L(Zn)synthesis,the core-shell structure of NiCo-MOF encapsulated in ZIF-L(Zn)was prepared(NiCo-MOF@ZIF-L(Zn))and was used as a precursor to obtain NiCo bimetallic N-doped carbon after pyrolysis.This catalyst exhibits good electrocatalytic oxygen reduction reaction(ORR)performance.By adjusting the ratio of Ni2+/Co2+ ratio in NiCo-MOF and the content of NiCo-MOF in final material,the electrocatalytic ORR activity of these materials was optimized.The material synthesized with Ni2+/Co2+ molar ratio of 1:1 shows the highest catalytic activity.2.The ZIF-67 layer was introduced to coat the NiCo-NC material.The obtained material retains morphology after pyrolysis from its parental NiCo-MOF@ZIF-L(Zn)@ZIF-67.The obtained NiCo-NC shows efficient ORR performane(E1/2=0.866 V;Eonset=0.982 V)and a better stability than that of commercial Pt/C.The rechargeable zinc-air battery constructed with NiCo-NC catalyst exhibits excellent electrocatalytic performance,with a power density of 243.4 mW cm-2 and a specific capacity of 792.8 mAh g-1 at 20 mA cm-2,good charging stability and can be continuously charged/discharged for more than 54 h at room temperature.3.2D cobalt sulfide material derived from ZIF-L was prepared and was used as self-sacrificial template through mild solvent thermal reaction.There are abundant S atoms exposed on the surface,which could form "Au-S" bond via strong interaction and realize the loading of Au particles on the outer surface.Finally,the"S-Au-Cys" structure was constructed to adsorb a large amount of hydrophilic cysteine(Cys)(the obtained material is denoted as ZIF-L-Co-S-Au-Cys.ZIF-L-Co-S-Au-Cys achieves high selectivity and efficient enrichment of N-containing glycosyl polypeptides from a mixture of peptides.