Preparation of Carbonized MOF/MgCl2 Hybrid Products as Dye Adsorbent and Supercapacitor: Morphology Evolution and Mg Salt Effect

Metal organic frameworks (MOFs) containing salt impurity provide a new idea for carbon material design. Presently, Mg–MOF/MgCl2 hybrid polycrystallines with different morphologies are solvothermally synthesized using 1,3,5-benzenetricarboxylic acid (BTC) or 1,4-benzenedicarboxylic acid (BDC) as the ligand, with or without polyethylene terephthalate (PET) inducer, respectively. After calcination, the products look like a flower, bud, cube, or nanosheet. When tested as adsorbent, the maximum methyl orange adsorption capacity reaches 3250 mg/g, the highest reported to date. The reason is attributed to the carbon-covered Mg salt inside the carbonized MOF. When tested as supercapacitor, carbonized MOFs based on BTC ligand show a high specific capacitance (127F/g) but a low rate capability, whereas a lower specific capacitance (121F/g) but a better rate capability (80% retention at 10A/g) are found for carbonized MOFs based on BDC. The reason is due to their different pore structures.