Highly Cuboid-Shaped Heterobimetallic Metal–Organic Frameworks Derived from Porous Co/ZnO/C Microrods with Improved Electromagnetic Wave Absorption Capabilities

Abstract

MOF-derived porous metal/C composites have drawn considerable attention from the microwave absorption field owing to their large pore volumes and surface areas (MOF: metal organic framework). Exploring single-MOF-derived materials with high-intensity and broadband absorption is largely needed, but remains a challenge. Here, porous Co/ZnO/C (CZC) microrods were fabricated easily from cuboid-shape heterobimetallic MOFs. CZC provides an efficient platform for integrating different semiconductors (ZnO), magnetic metal (Co) and carbon sources into one particle, which enhances the electromagnetic wave absorbing ability. The carbonization temperature which is critical for electromagnetic parameters was studied in detail. CZC annealed at 700 °C outperformed those obtained at 600 or 800 °C in terms of microwave wave absorbing properties. The reflection loss (RL) was optimized to -52.6 (or -20.6) dB at 12.1 (or 14.8) GHz with effective bandwidth (RL≤-10 dB) of 4.9 (or 5.8) GHz at the coating thickness of 3.0 (or 2.5) mm. Such enhancement of EM wave absorbing capabilities is ascribed to the well-built porous structure, dielectric loss and magnetic loss. This work offers a new way to prepare porous magnetic metal/C composites with excellent microwave absorbing properties starting from heterobimetallic MOFs.