Template-free synthesis of millimeter-scale carbon nanorod arrays on boron-doped diamond with superior glucose sensing performance

Abstract Large-scale growth of three-dimensional (3D) carbon nanostructure via a template-free method remains challenging. In this work, a millimeter-scale carbon nanorod array (CNA), via thermal catalysis with nickel as the catalyst, is directly synthesized on the substrate of boron-doped diamond (BDD). Electron microscopies evidence the phenomena of independent growth of a single carbon nanorod and the fusion of two or more nanorods, and demonstrate that the inner area of carbon nanorod is not hollow but amorphous carbon, while the outer area reveals the layered graphite structure. The small biomolecule, D-(+)-glucose, is chosen as the standard to test its sensing performance. Electrochemical results demonstrate the CNA/BDD electrode can detect as low as 0.5 μM glucose and has a superior sensitivity of 1740.1 μAmM-1cm-2, showing the most outstanding performance compared to the other reported BDD-based electrodes. The superior sensing performance benefits from synergistic effects of catalysis of nickel nanoparticles anchored on CNA and BBD, the enhanced electroactive surface area and mass transfer rate due to the three-dimensional nanostructure.