A novel Cr2O3 coated CNTs system: Synthesis, microstructure regulation, and characterization

Surface modification is an attractive strategy for expanding, improving, or altering the properties and functions of carbon nanotubes (CNTs), which opens up a broad range of novel applications. Herein, a simple, and efficient approach for the synthesis of the Cr2O3 coated CNTs system was developed, and the morphologies and microstructures of the coating on CNTs along with annealing temperature were systematically investigated. It was found the continuous amorphous (Cr2O3)1/2·(H2O)3/2 coating with a thickness of about 3–4 nm can be decorated onto CNTs with the applied coating processes, and which can be transformed into continuous amorphous Cr2O3 coating after annealing at 500 °C for 0.5 h. With further increasing the annealing temperature to 700 °C, nano Cr2O3 particles with high crystallinity were formed at the expense of amorphous Cr2O3 coating, and the coating on the surface of CNTs can be completely consumed for transforming into crystalline Cr2O3 nanoparticles when the annealing temperature is up to 800 °C. The findings provide important guidance for the surface modification of CNTs and lay the foundation for the industrial application of the novel Cr2O3 coated CNTs.