Microwave absorption properties of rod-shaped Co–Ni–P shells prepared by metallizing Bacillus

The rod-shaped Co–Ni–P shells were prepared by metalling Bacillus. The microstructures and composition of the shells were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive analysis (EDS). The electromagnetic parameters were measured by the coaxial line method in the frequency of 2–18 GHz. It was found that the Bacillus were successfully coated with Co–Ni–P, and the inner structure of the shells are hollow in structure. The shells exhibit excellent microwave absorption properties in 5–17 GHz frequency. The microwave reflection loss is above −10 dB in 5.38–16.6 GHz frequency. The maximum microwave reflection loss reaches −35.83 dB at 9.12 GHz for samples thickness 2.4 mm, and the widest bandwidth for microwave reflection loss above −10 dB is about ∼5.32 GHz for samples thickness 2.0 mm. These results confirm the feasibility of applying Bacillus as biotemplates for fabrication of the metallic shells as lightweight microwave absorption materials are very promising for applications.