Co/CeO₂/C composites derived from bimetallic metal-organic frameworks for efficient microwave absorption

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• Cerium dioxide (CeO2) is an n-type semiconductor with inherent properties suitable for microwave absorption (MA).
• Structural features like oxygen vacancies and interstitial atoms in CeO2 contribute to its MA capabilities.
• Developing advanced composite materials can further optimize MA performance.

Purpose of the Study:

• To synthesize and characterize Co/CeO2/C composites for microwave absorption.
• To investigate the influence of pyrolysis temperature on the MA properties of the composites.
• To elucidate the mechanisms behind the enhanced MA performance.

Main Methods:

• Hydrothermal synthesis followed by pyrolysis to create Co/CeO2/C composites.
• Systematic variation of pyrolysis temperatures from 650 °C to 950 °C.
• Evaluation of microwave absorption performance across the 2-18 GHz frequency range.

Main Results:

• The Co/CeO2/C composite pyrolyzed at 850 °C (Co/CeO2/C-850) showed superior MA properties.
• RLmin of -45.22 dB and an effective absorption bandwidth (EAB) of 4.61 GHz were achieved at 1.75 mm thickness.
• Enhanced MA performance is linked to dielectric loss (interfacial and dipole polarization) and magnetic loss.

Conclusions:

• Pyrolysis temperature significantly impacts the microwave absorption characteristics of Co/CeO2/C composites.
• The Co/CeO2/C-850 composite demonstrates excellent potential as a lightweight and effective microwave absorber.
• Synergistic effects between dielectric and magnetic losses, along with optimized impedance matching, contribute to the outstanding performance.