Metal-organic framework-derived CoSn/NC nanocubes as absorbers for electromagnetic wave attenuation

Metal-organic framework-derived composites have been widely used in electromagnetic wave (EMW) absorption, but the traditional synthetic strategy greatly limits the structure and species of MOFs. This research provided a solvent-free method to synthesize Co-MOF and its derivatives. Using CoSnO3 as the precursor, the preparation of Co-MOF is achieved by bridging the cobalt (II) ion of CoSnO3 and the 2-methylimidazole skeleton. The CoSn/N-doped carbon (CoSn/NC) composites derived from CoSnO3-MOF (Co-MOF with CoSnO3 as Co source) retain the original morphology of CoSnO3. Besides, the polarization effect produced by the N-doped carbon layers also benefits the excellent EMW absorption performance of the CoSn/NC composites. It is reflected in the minimum reflection loss (RL) of -48.2 dB at 2.2 mm and the effective bandwidth (EBA) of 5.84 GHz. This work provides a new channel to the construction of Co-MOFs, which could be extended to other Co-based oxides and vastly expand the species of MOFs based on metallic Co.