Joule Heating-Driven sp2-C Domains Modulation in Biomass Carbon for High-Performance Bifunctional Oxygen Electrocatalysis
Jiawei He, Yuying Zhao, Lijun Yang, Qixin Yuan, Yuhan Wu, Kui Wang, Kang Sun, Jingjie Wu, Jianchun Jiang, Baohua Zhang, Liang Wang, Mengmeng Fan
Abstract
Abstract Natural biomass-derived carbon material is one promising alternative to traditional graphene-based catalyst for oxygen electrocatalysis. However, their electrocatalytic performance were constrained by the limited modulating strategy. Herein, using N-doped commercial coconut shell-derived activated carbon (AC) as catalyst model, the controllably enhanced sp 2 -C domains, through an flash Joule heating process, effectively improve the edge defect density and overall graphitization degree of AC catalyst, which tunes the electronic structure of N configurations and accelerates electron transfer, leading to excellent oxygen reduction reaction performance (half-wave potential of 0.884 V RHE , equivalent to commercial 20% Pt/C, with a higher kinetic current density of 5.88 mA cm −2 ) and oxygen evolution reaction activity (overpotential of 295 mV at 10 mA cm 2 ). In a Zn-air battery, the catalyst shows outstanding cycle stability (over 1200 h) and a peak power density of 121 mW cm −2 , surpassing commercial Pt/C and RuO 2 catalysts. Density functional theory simulation reveals that the enhanced catalytic activity arises from the axial regulation of local sp 2 -C domains. This work establishes a robust strategy for sp 2 -C domain modulation, offering broad applicability in natural biomass-based carbon catalysts for electrocatalysis.