Chirality induces the self-assembly generating 3D porous spiral-like polyhedron as metal-free electrocatalysts for the Oxygen Reduction Reaction.

The sluggish kinetics and large overpotential of oxygen reduction reaction (ORR) severely limit the widespread production and application of metal-air batteries. Herein, a conductive 3D porous spiral-like polyhedron structures composed of nitrogen-doped carbon nanosheets (L/D-SPNC), was utilized as catalysts with combination of 3D hierarchical porous properties and distinguishing intrinsic properties of 2D nanosheets for ORR. The chiral template, L/D-Tartaric acid, induces the self-assembly of supramolecular and the formation of orderly array of carbon with spiral-like surface feature on a molecular scale. The resulting L/D-SPNC exhibits small wall thickness (2.5 nm), large specific surface area (2034.2 m²/g) and high conductivity (155.76 S/m), which indicates the properties of 2D nanosheets building blocks are kept in 3D mode. As catalysts for ORR, the optimized L-SPNC-950-1 exhibits a more positive onset potential 1.03 V compared with those of Pt/C (1.00 V), and a halfwave potential of 0.87 V is also comparable to those of Pt/C (0.87V). Al-air batteries discharge data demonstrate that spiral-like structure facilitates the diffusion of electrolyte and oxygen on three-phase interface causing weak-polarization. DFT calculations prove that twisted surface aggravate the differential charge distribution between C-C/C-N bonds.