Single‐Atomic Ni‐N ₄ Biofuel Cell for Mimicking Intramolecular Electron‐Harnessing of Laccase

Abstract

Abstract Ni–N 4 –PAN–NC, consisting of an atomic Ni–N 4  site, mimics the intramolecular electron‐harnessing of natural laccase (LAC) confined in a zeolitic imidazolate framework‐8 (LAC@ZIF‐8) for anodic electrooxidation of bisphenol‐A (BPA). We have introduced a facile π‐conjugated unit of polyacrylonitrile (PAN)‐resorcinol‐derived N‐doped conjugated ‐C≡N. The atomically dispersed Ni‐single‐atom in Ni–N 4 ‐ PAN–NC exhibits high activity for the paired electrolysis of ORR and the electrooxidation of BPA with an enhanced current density. The single Ni–N 4– PAN–NC electrode effectively withdraws the electrons from electrooxidizing BPA due to a built‐in electric field via incorporation of Ni–N 4 . The paired electrolysis of Ni–N 4– PAN–NC biofuel cells is determined by LSV, EIS, and power‐polarization curve for anodic electrooxidation of BPA. Machine learning molecular dynamics (ML‐MD) simulation depicts non‐covalent interaction (hydrogen bonding) between the O‐hydroxyl of BPA and the N of the Ni–N 4– PAN–NC, suggesting preferential adsorption on the Ni–N 4– PAN–NC surface via weak van der Waals interactions and π–π stacking between the aromatic rings of BPA and the conjugated PAN‐NC. An increased power density with increased concentration of BPA in the absence of ABTS suggests a DET mechanism of BPA electrooxidation on Ni–N 4 , unlike a MET in the presence of ABTS when using LAC@ZIF‐8. Thus, single atomic Ni − N 4  opens avenues with a DET mechanism.