Sustainable Preparation of Waste Heavy Bio-oil Based 3D Porous Carbon Materials via In-Situ Binary Template Activation and Its Application in Zinc-Ion Hybrid Capacitors

Abstract

As a liquid by-product generated during biomass pyrolysis, heavy bio-oil (HBO) possesses characteristics of high carbon content, excellent thermoplasticity, and easy polycondensation. Research on upgrading HBO into functional porous activated carbon (PAC) materials has attracted significant attention. This study developed an innovative and mild one-step binary green pyrolysis activation strategy, using HBO as a carbon precursor to fabricate high-quality PAC for electrochemical energy storage. By rationally tuning the activator dosage, PAC with coexisting micropores and mesopores can be directionally synthesized. Notably, BOAC-4 prepared at an HBO:activator:template mass ratio of 2:2:1 exhibits an excellent specific surface area (2136 m 2 /g) and ideal pore structure (31% mesoporous rate), delivering optimal electrochemical performance in three-electrode systems (325 F/g specific capacitance at 0.5 A/g). Meanwhile, BOAC-4 have also demonstrated excellent performance in zinc-ion hybird capacitor systems. This study combined Raman, TEM, and GPC characterizations to reveal the synergistic mechanism of MgO template's spatial confinement "bridging" effect and K 2 C 2 O 4 activator's hierarchical "etching" pore-forming role during binary green pyrolysis activation, constructing PAC with rational micro-mesoporous ratios and ultra-microporous properties, thereby enhancing their electrochemical performance. This study proposes a green one-step pyrolysis activation strategy for preparing PAC from HBO, offering sustainable solutions to resource recycling and environmental challenges.