Thin-film nanocomposites of BDD/CNT deposited on carbon fiber

Abstract

The nanocomposites of porous boron-doped diamond deposited on carbon nanotubes (BDD/CNTs) present great surface area and high capacitance, making them a material of considerable interest for application in electrochemistry. In this work, we present a new approach in which this nanocomposite is deposited on carbon fiber (CF) to increase the surface area and the capacitance comparing to the unsized CF electrode. We performed the dip-coating for catalyst deposition on CF surface. After, CNTs growth followed in a tubular reactor at 650°C for 20min, using camphor in a 200g/L hexane solution as the carbon source. Electrostatic Self Assembly (ESA) seeding of nanodiamond (ND) went on by grafting polar groups onto CNTs surface by oxygen plasma functionalization. The seeding process was made with 4nm diamond nanoparticles dispersed in KCl aqueous solution. The BDD films were deposited by Hot Filament Chemical Vapor Deposition (HFCVD) reactor. The authors studied the composites morphology, structure and electrochemical properties by Scanning Electron Microscopy with Field Emission Gun (FEG-SEM), Raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). This new material presented larger surface area and higher capacitance compared to CF without treatment, as presented in electrochemical analysis results. The SEM micrographs showed absence of metallic particles on CNTs structure, what promoted a better quality diamond growth.