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

Abstract

One-dimensional (1D) metal-organic nanostructures hold great promise for preparing various 1D carbon/metal derivatives toward various electrocatalysis including oxygen reduction reaction (ORR); but it is challenging to synthesize them. Herein, 1D cobalt(Co)-metal-organic nanowires are prepared using 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 reveal that the Co@CNB can strengthen the adsorption of all adsorbates (O*, OH* and OOH*) compared with a carbon nanotube, benifical for oxygen protonation and thus 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 shows 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.