Nitrogen-doped carbon shell structure derived from natural leaves as a potential catalyst for oxygen reduction reaction

Implementation of non-precious electrocatalysts towards oxygen reduction reaction (ORR) falls in the central focus on fulfilling cost-affordable and high-performance fuel cells and metal/air batteries. Recent first-principles spin-polarized OFT calculations simulated the electrocatalytic ORR reaction process on N-doped C-60 fullerene (N-C-60) and found that O-2 can be chemisorbed and reduced on N-C-60, indicating that N-C-60 is a potential cathode catalyst for hydrogen fuel cells. In this work, a novel waste-to-resource strategy to convert fallen ginkgo leaves into this new kind of ORR electrocatalyst, nitrogen-doped fullerene-like carbon shell (NDCS), is presented. N is derived from fallen ginkgo leaves, where 10.9-15.5 wt% proteins are present. The obtained NDCS possesses 100% catalysis selectivity towards four-electron pathway, and its ORR activities outperform most of the other existing carbon-based catalysts. It also shows significantly improved tolerance against methanol and enhanced long-term stability, compared with the commercial platinum-loaded carbon catalyst. Thus it is experimentally demonstrated that the NDCS is a promising future ORR catalyst, which is well consistent with the quantum mechanics calculations. Additionally, the NDCS presents a high reversible capacity (750 mA h g(-1) at 0.02 A/g) in Li-ion batteries. Since fallen ginkgo leaves are readily available, our study represents an exciting direction for sustainable and low-cost energy conversion and storage materials. (C) 2015 Elsevier Ltd. All rights reserved.