Spiral effect of helical carbon nanorods boosting electrocatalysis of oxygen reduction reaction

Abstract

Helical metal-organic frameworks (MOFs) were used as templates or precursors to fabricate helical carbon nanorods (HCNRs) for the first time. Helical carbon contains many topological defects such as pentagonal or heptagonal carbons, which have the potential to facilitate oxygen reduction reactions (ORR). HCNRs show more positive onset/half-wave reduction potentials and higher limited current density than straight carbon nanorods (SCNRs). They also exhibit four-electron oxygen reduction in tests of ORR, while the alternative SCNRs prefer a two-electron reduction mechanism. Experimental and theoretical studies reveal that these enhanced ORR activities can be attributed to pentagon/heptagon defects in HCNRs. This work provides an effective strategy to synthesize helical, defect-rich carbon materials and opens up a new perspective for utilization of a spiral effect for the development of more effective electrocatalysts.