Incorporate boron and nitrogen into graphene to make BCN hybrid nanosheets with enhanced microwave absorbing properties

This work demonstrates the conversion of graphene oxide into BCN hybrid nanosheets by reaction with boric acid and urea at 900 °C, during which boron and nitrogen atoms are incorporated into the graphene atomic sheets. X-ray diffraction pattern and X-ray photoelectron spectroscopy reveal the existence of h-BN. High-resolution electron microscopy and Raman spectrum indicate the presence of graphene-like layers with h-BN nanodomains. The content of h-BN in the BCN nanosheets can also be tuned by further heat-treatment in an ammonia environment, which in turn affects the band gap of these nanosheets. The electromagnetic parameters suggest that these samples can be used as good microwave absorbing materials at G band (5.6-8.2 GHz) and X band (8.2-12.4 GHz). This study provides a simple route to BCN hybrid nanosheets with tunable band gap and adjustable conductivity for microwave absorbing applications.