Carbon nanostructures grown on 3D silicon carbide foams: Role of intermediate silica layer and metal growth

Abstract

• Carbon nanostructures (CNSs) were grown on 3D silicon carbide foams. • SiC foams were coated with intermediate mesoporous silica layers. • Effect of metal growth on the morphology of CNSs were studied. • Uniformity of CNSs can be obtained at a mild temperature of 700 °C. Carbon nanostructures (CNSs) in the form of fibers and spheres have been successfully grown on 3 dimensional (3D) macroscopic silicon carbide (SiC) foams with the aid of mesoporous silica-films as interfacial layer via ethylene decomposition on nickel and iron as growth catalysts using chemical vapor deposition (CVD). The effect of growth temperature from 600 to 900 °C on morphology, diameter and specific surface area of as-grown CNSs was studied. The as-grown CNSs were characterized by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) to examine the morphology, diameter, microstructure and defect. Crystallinity and degree of graphitization were determined by X-ray diffraction and Raman spectrometer. Textural properties such as specific surface area, pore size and pore volume were measured by nitrogen gas adsorption–desorption. Uniform distribution of CNSs on 3D SiC-foam was obtained at 700 °C for short synthesis time (30 min), as well as high surface area of above 100 m 2 /g. Degree of graphitization of CNSs grown on modified SiC substrates by using Ni as growth catalyst was higher than the one with the Fe-growth catalyst.