Orange Peel Derived-Nitrogen and Sulfur Co-doped Carbon Dots: a Nano-booster for Enhancing ORR Electrocatalytic Performance of 3D Graphene Networks

Herein, nitrogen, sulfur co-doped carbon dots (N,S-CDs) have been synthesized by a cost-natural fabrication method using waste orange-peel as a natural-carbon-precursor. N,S-CDs have been hydrothermally anchored to the three-dimensional-graphene-networks (3D-GNs) to boost the electrocatalytic activity by a defective surface effect. Due to the synergistic utilization of heteroatoms, and effective mass-transfer and improved transport kinetics resulting from interconnected 3D-architecture, N,S-CDs anchored 3D-GNs (N,S-CDs@3D-GNs) grant superior oxygen-reduction-reaction (ORR) activity. N,S-CDs@3D-GNs exhibit a dominant four-electron pathway (n=3.89) for ORR in alkaline media besides superior methanol tolerance and robust stability. This work opens a door for converting low-value agricultural wastes into value-added materials for utilizing in energy application.

Automated summary

Nitrogen and sulfur co-doped carbon dots were synthesized using waste orange peel as a natural carbon precursor, and anchored to three-dimensional graphene networks to enhance electrocatalytic activity. The synergistic utilization of heteroatoms and interconnected 3D architecture resulted in superior oxygen reduction reaction activity in the alkaline media. This study demonstrates the potential of converting low-value agricultural wastes into value-added materials for energy applications.