Research On The Pyrolysis Behavior Of MOFs And The Photothermal Properties Of Their Pyrolysis Products

Metal Organic Frameworks(MOFs)refer to porous crystalline materials formed by the interaction of Metal ions or clusters of Metal ions and one or more small Organic molecules by coordination bonds.Most MOFs have ordered pore structures and can provide carbon sources,templates and metal elements at the same time.Therefore,carbon materials with rich morphologies can be obtained by direct pyrolysis of MOFs as precursors.The purpose of this project is to systematically study the pyrolysis process of MOFs materials by selecting MOFs with different configurations as precursors,and then design and prepare carbon nanostructures with controllable structure and composition.In this paper,three MOFs with three configurations were selected as the research objects.Cluster-based MOFs represented by Zn-bpdc-ad were selected respectively.The rod-like stacked MOFs represented by Zn-terephthalic acid-lactic acid(Zn-BDC-lac)and the lamellar columnar MOFs represented by cobalt-(3-hydroxy-2-picolinic acid)-isonicotinic acid(Co-pico-ina).Firstly,the pyrolysis process of three MOFs was studied in situ by Drift and TG-MS.It was found that there were significant differences in the intermolecular and intramolecular chemical bond strength during the pyrolysis process of three MOFs with different configurations.Therefore,the pyrolysis process of all levels of MOFs also has a sequence.Finally,the carbonized products with different morphologies and structures were tested as photothermal materials and the photothermal conversion efficiency was calculated.At the same time,the pore structure data of the two series of samples were tested,and the factors affecting the photothermal conversion efficiency of the carbon materials were analyzed.The time and heat conversion efficiency of Zn-bpdc-ad pyrolysis products is the highest at 700℃,which is 45.77%.The maximum time-heat conversion efficiency of Zn-BDC-lac pyrolysis products is 39.19%at 800℃.