High-Yield\nTwo-Dimensional Metal–Organic Framework\nDerivatives for Wideband Electromagnetic Wave Absorption

Abstract

Two-dimensional metal–organic frameworks\n(2D-MOFs) and their\nderivatives are promising for catalysis, energy storage, gas separation,\netc. due to their unique microstructure and physicochemical properties.\nMany efforts have been devoted to fabricating 2D-MOFs with challenges\nremaining in yield and fine control of their thickness and lateral\nsize. Here a versatile strategy has been used involving epitaxial,\nanisotropic, and confined growth of CoNi-MOF-71 nanosheet arrays,\ngiving rise to excellent quantity and controllability of the 2D-MOFs.\nElectromagnetic (EM) wave absorption performance has been investigated\nfor the resultant 2D Co/Ni/C derivatives. Compared with the bulk counterpart,\nsignificantly increased surface area, conductivity, and shape anisotropy\nfor the 2D derivatives result in enhanced interfacial polarization,\nconductive loss, and magnetic resonance. As such, optimum EM wave\nabsorption of minimum reflection loss RL_min = −49.8\ndB and an ultrawide effective adsorption bandwidth EAB = 7.6 GHz can\nbe achieved at a thickness of 2.6 mm. This work not only sheds light\non the performance enhancement for 2D absorbers via synergistic effects\nof multiple attenuation mechanisms but also provides an effective\nfabrication route of ultrathin MOFs with high yield and uniform size\nfor extended applications in catalysis, electrochemistry, and optoelectronics\nfields.