Biomass-Derived Nitrogen and Sulfur Co-Doped Carbon Microtubes for Oxygen Reduction Reaction

The development of environmentally friendly methods for fabrication of new energy materials has been always pursued in relieving the global environmental and energy issues. During the past decade, carbon-based metal-free electrocatalysts with enhanced electrocatalytic performances by multiple heteroatom doping and superior electrical conductivity have shown their great potential to replace noble metal electrocatalysts in fuel cells. However, it remains challenging for the fabrication of highly efficient carbon-based electrocatalysts from biomass and environmental waste. Herein, we report the facile and scalable fabrication of nitrogen and sulfur co-doped carbon microtubes (N, S-CMTs) by pyrolysis of catkins (environmental pollutant) having adsorbed toxic dyes (water contaminant). With optimized parameters such as conductivity, doping, porosity, and surface area, the N, S-CMTs demonstrate significantly enhanced electrocatalytic performances in oxygen reduction reaction (ORR) compared with those of commercial 20 % Pt/C. Our work offers a promising alternative to platinum-based electrocatalysts toward ORR in fuel cell applications.