N and S Dual-Doped Mesoporous Carbon Nanostructure as a High Performance and Durable Metal Free Oxygen Reduction Reaction Electrocatalyst

Abstract

Discovering a high performance, durable, and cost-effective oxygen reduction reaction (ORR) electrocatalyst is a key strategy for widespread use of the high efficiency and environmentally friendly fuel cell and metal-air battery technologies. Herein, we fabricate a high performance and durable metal free N and S dual-doped mesoporous carbon nanostructure (NS-VXC) ORR catalyst using solid state thermolysis at 700 °C for 1 h. The fabricated catalyst exhibits nanocarbon aggregated chain-like morphology with a high surface area and mesoporous structure. The amount of N and S dopants embedded in mesoporous carbon nanostructure is found to be 3.2 and 1.1%, respectively which significantly attribute to the synergistic effect of spin and charge density leading to not only superior ORR performance but excellent durability in the alkaline environment as well. Rotating ring disk electrode analysis reveals the codoped NS-VXC catalyst possesses a direct 4-electron transfer number pathway with extremely low peroxide intermediate content. Compared to the benchmark Pt/C catalyst, the fabricated NS-VXC catalyst generated 10 mV ORR performance outperform and negligible performance degradation after the 10,000 ORR cycling test. These results suggest that an innovative solid state thermolysis methodology can be a powerful nanomaterial fabrication technique to generate high performance and excellent durability electrocatalyst for green energy applications.