Template Free Growth of Cobalt Catalyst-Assisted Horizontally Aligned Carbon Nanorod Arrays by MW-CVD Utilizing Mild Oxidant in the Plasma

The synthesis of three-dimensional carbon nanostructures without templates remains a substantial challenge. The present research enables skillfully generating horizontally -aligned carbon-nanorod-arrays (HA-CNRA), using microwave plasma -enhanced chemical vapor deposition (MW-PECVD) on quartz substrates coated with Co catalyst layers annealed at diverse temperatures. In this method, a gas mixture comprising C 2 H 2 , H 2 , and CO 2 was used for the CNRA growth at a low substrate temperature of -300 degrees C. Electron -microscopy observation confirms the autonomous growth of individual hollow CNRs. A discernible peak at 1340 cm -1 , G band peak at 1596 cm -1 , and 2670 cm -1 peak (2D band) were observed, indicating a well -graphitized feature of the CNRs, which was further ascertained by the corresponding X-ray diffraction planes of (002) and (101) orientations. In the optimally grown film, a homogeneous array of nanorods with an average diameter of -450 nm was obtained. The C 1 s spectra peaked at 284.6 eV confirming the presence of crystalline sp 2 -hybridized nanorods. The novelty of the work lies in enabling the Co catalyst -assisted template -free growth of HA-CNRA by low -temperature MW-CVD, utilizing the reactant atomic species like H and O from the (C 2 H 2 + H 2 + CO 2 )-plasma and preserving the growth continuity through a specific shadow masking configuration deployed atop the developing plane, thereby inducting a diffuse plasma on the substrate and restricting the direct collision of energetic particles with the developing network. Due to the adjustable size, shape, and advantageous architectural characteristics, horizontally -aligned CNRA manifests significant potential as electrode materials for energy storage applications, specifically in batteries and electrochemical capacitors.