Porosity and composition of nitrogen-doped carbon materials templated by the thermolysis products of calcium tartrate and their performance in electrochemical capacitors

Porous nitrogen-doped carbon materials were synthesized by chemical vapor deposition method using template nanoparticles produced by the decomposition of calcium tartrate in thermal shock conditions. The synthesis temperature was varied from 650 degrees to 900 degrees C with a step of 50 degrees C and acetonitrile vapor was supplied into reactor immediately after the template formation. Transmission electron microscopy and X-ray diffraction analysis detected an increase of the number of ordered graphitic layers with the rise of the synthesis temperature. That was accompanied by a decrease of the specific surface area and the total pore volume determined from N-2 adsorption measurements. Higher surface area of the materials produced at 650 and 700 degrees C was assigned to the co-existence of CaCO3 and CaO template nanoparticles at these temperatures. X-ray photoelectron spectroscopy found about 4-5 at% of nitrogen in all materials and a strong temperature-dependence of the ratio of nitrogen forms. The material synthesized at 750 degrees C showed the best electrochemical performance in 1 M H2SO4 electrolyte due to the presence of large fraction of pyridinic nitrogen responsible for pseudo-capacitance, graphitic nitrogen promoting charge transport, and large-size mesopores providing the fast diffusion of electrolyte ions. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Porous nitrogen-doped carbon materials were synthesized using template nanoparticles produced by the decomposition of calcium tartrate in thermal shock conditions. Increasing the synthesis temperature led to more ordered graphitic layers but decreased specific surface area and total pore volume. The material synthesized at 750 degrees Celsius showed the best electrochemical performance due to the presence of pyridinic nitrogen, graphitic nitrogen, and large-size mesopores.