One-dimensional metal-organic nanowires-derived catalyst of carbon nanobamboos with encapsulated cobalt nanoparticles for oxygen reduction

Abstract One-dimensional (1D) metal-organic nanostructures holds great promise for preparing various 1D carbon/metal derivatives toward various electrocatalysis including oxygen reduction reaction (ORR); but it is challenge to synthesize them. Herein, 1D cobalt(Co)-metal-organic nanowires are prepared through the complex of Co2+ and 1, 2, 4-triazole. Direct carbonization of the as-prepared nanowires affords a well-defined structure of Co nanoparticles encapsulated inside the bamboo-liked 1D carbon nanostructure, i.e., carbon nanobamboos (Co@CNB). Owing to the outstanding electronic transport in bamboo-liked carbon structure, strong electronic coupling between the N-doped carbon and Co nanoparticles, the Co@CNB catalyst exhibits an excellent ORR performance comparable to the commercial Pt/C in alkaline solution. Density functional theory (DFT) calculations revealed that the Co@CNB can strengthen the adsorption of all adsorbates (O*, OH* and OOH*) compared with a pure carbon nanotube. A benefit of oxygen protonation enhancing the ORR activity. Moreover, it is possible to outperform Pt intrinsically if the curvature of carbon shell is high enough in Co@CNB. Lastly, the zinc-air battery (ZAB) fabricated with Co@CNB as the cathode catalyst presents a higher peak power density and better cycling durability than those of the ZAB with Pt/C; suggesting the great potential of Co@CNB as efficient electrocatalysts for metal-air batteries.