N–S-codoped mesoporous carbons from melamine-2-thenaldehyde polymers on carbon nanotubes for oxygen reduction and Zn-air batteries

Abstract

Low-cost melamine and 2-thenaldehyde were assembled into N, S-enriched polymers supporting on commercially carbon nanotubes (CNTs) by one-pot synthesis method. The direct carbonization of this composite precursors harvested the metal-free carbons with synergistic doping of N and S atoms without post-treatment. Abundant large-pore mesopores were formed in the derived N–S–Cs with higher surface area. Higher graphitization degree of N–S–Cs endow it with the low resistance and fast electron conductivity. As a result, the N–S–Cs-900 exhibited as an efficient cathode catalyst for oxygen reduction reaction (ORR) especially in alkaline electrolyte, with positive ORR half-wave potential and higher limiting current density. In addition, the metal-free N–S–C materials also had better performance in Zn-air batteries with an initial voltage gap with 1.487 ​V. This work developed a low-cost synthesis strategy to obtain metal-free N–S–Cs with impressive ORR performance.