Metal-free nitrogen-rich carbon foam derived from amino acids for the oxygen reduction reaction

Abstract

The following paper presents the synthesis of nitrogen-rich carbon foams (N-CFO) from amino acids through their thermal decomposition in the presence of solid and removable nanoparticles (template). N-CFO were synthesized by carbonizing l-lysine as the carbon phase precursor and using a hard template of CaCO3 (added as nano-sized powder). The carbonization process was carried out in a temperature range of 700–900 °C, under the flow of nitrogen. The results show that the textural and chemical properties among other nitrogen content of the N-CFO can be controlled by manipulating carbonization temperature. The obtained N-CFO were either micro- or mesoporous matrixes (open porosity) with high nitrogen content in the range from 4.1 to 12.4 wt%. The walls of the produced N-CFO had a thickness up to 10 nm. The metal-free catalysts such as N-rich carbon foams are valuable materials in oxygen reduction reaction, which is a key reaction for metal–air batteries. It was found that a four-electron reduction process is predominant.