Interfullerene Spacing Regulates Fragment Reconstruction toward Defect-Rich Carbon Electrocatalysts

Fullerene reconstruction has emerged as a potent route to discover new carbon forms with exciting structural and physiochemical properties. However, rationally controlling the reconstruction process toward targeted carbon products, particularly metastable intrinsic defect-rich catalysts, remains a challenging task. Here, we report a fullerene derivatization strategy to tune the intercage spacing that governs the orbital hybridization and defect states of reconstructed carbon. Self-assembled C60-pyrrolidine and C60 crystals that present varied morphologies and sizes are restructured to defective carbons as electrocatalysts toward oxygen reduction reaction (ORR). Lower spatial proximity, afforded by a smaller crystal size and enlarged intercage spacing of C60-pyrrolidine (11.74 Å) relative to that of C60 (9.99 Å), results in a higher sp2/sp3 ratio and more pentagon defects. A pivotal structure–property relationship is unraveled in which the sp2/sp3 ratio, electrical conductivity, and ORR activity of derived carbons are all linearly correlated. In situ Raman spectroscopy reveals that the best catalyst proceeds via the associative 4e–-ORR pathway. Theoretical calculations point out that in-plane pentagons, which induce a high surface Gaussian curvature, show a lower energy barrier for *OOH formation than edged pentagons. High applicability of this carbon is further testified as an impressive cathode catalyst beyond Pt/C for both aqua- and flexible gel-based zinc–air batteries.