The influence of layered double hydroxide composition on the morphology, porosity and capacitive properties of nitrogen-doped carbon materials prepared via chemical vapor deposition

Abstract

Porous N-doped carbon materials of various morphologies are prepared via chemical vapor deposition (CVD) at 700°C using acetonitrile as carbon and nitrogen source and MgAl, MgCoAl, CoAl layered double hydroxides (LDHs) as template and catalyst precursors. The physicochemical properties of the carbon materials are characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetric analysis, elemental analysis, nitrogen sorption and n-nonane thermodesorption, whereas their electrochemical performance is evaluated in 6M KOH by means of cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy. The choice of LDHs strongly affects the grain morphology and micropore/mesopore contribution in the synthesized carbon materials, which determines their capacitive performance. The application of Co-free LDHs leads to the carbon material consisting of irregular aggregates of plate-like particles highly doped with nitrogen (9.7wt%) and having high specific surface area (863m2g−1) and high capacitance (130Fg−1). On the other hand, the use of Co-containing LDHs results in the carbon materials predominantly made of carbon nanotubes (grown on metallic Co nanoparticles) less doped with nitrogen (2.4–3.1wt%) and having lower specific surface area (193–225m2g−1) and lower capacitance (15–30Fg−1).