Fabrication Of Metal-Organic Framewok And Infinite Coordination Polymers Nanosheets By The Spray Technique

Over the past decades,metal-organic frameworks(MOF)and infinite coordination polymers(ICP)have attracted much attention because of their porous structures,channel functionalities,and structural tailorability,which leads to wide range of potential applications.In particular,making these materials into two-dimensional(2D)nanosheets is highly desirable because of the intriguing physical and chemical properties that are rarely present in bulk materials.In this context,nanosheets are usually considered to be promising candidates for gas separation,energy storage(batteries and solar cells),chemical sensors,catalysis,and other applications in the field of nanotechnology.With regard to ICP,the fabrication of ICP nanosheets has rarely been reported so far,and the preparation of spherical ICP particles has been the focus.As for MOF nanosheets,fabrication approaches have been developed mainly in two ways,which are top-down exfoliation and bottom-up growth.Top-down exfoliation relies on the disintegration of bulk layered materials into single layers or multiple layers with large lateral dimensions.However,the morphological damage,the reaggregation,and even the introduction of impurities into the exfoliation process are difficult to avoid.Therefore,plenty of effort has been spent on the bottom-up growth strategy,which normally produces nanosheets at their genesis by either enhancing anisotropic crystal growth or restricting thermodynamically favored layer stacking.Recently,a novel bottom-up growth strategy for preparing MOF nanosheets by a three-layer method has been reported.rapid and convenient preparation of two-dimensional MOF and ICP nanosheets is limited,so the development of a rapid and convenient preparation of two-dimensional MOF and ICP nanosheets is urgent and necessary.We have developed a rapid and convenient method for fabricating Metal-Organic Framework(MOF)and Infinite Coordination Polymer(ICP)nanosheets by spraying the atomized solution of metal ions onto the organic ligand solution.Nanosheet formation could be attributed to the anisotropic diffusion of metal ions in the ligand solution,which may give rise to a lateral interface of metal ions and organic ligands,where the crystals tend to grow laterally in the form of nanosheets.Three kinds of Zn-and Cu-based MOF nanosheets and two kinds of Co-based ICP nanosheets have been successfully obtained by spraying under mild conditions.The two-dimensional structures of nanosheets with a nanometer thickness and a homogeneous size can be evidenced by scanning electron microscopy,atomic force microscopy,X-ray diffraction,Brunauer-Emmett-Teller,and Fourier transform infrared spectroscopy measurements-Furthermore,the fabricated ICP nanosheets have exhibited efficient catalytic performance for the conversion of CO2 to high-value-added chemicals.This spray technique simplifies the nanosheet production process by industrialized means and enhances its controllability by the fast liquid-liquid interfacial fabrication,thus allowing access to the industrialized fabrication of MOF and ICP nanosheets.