KOH-activated co-pyrolysis of petroleum coke with lignocellulosic biomass model compound: sulfur-cleansed hierarchical porous carbon for high-performance supercapacitors

Petroleum coke (PC) is characterized by its high carbon content and low cost, but its elevated sulfur content and dense structural configuration constrain high-value utilization and electrochemical applications. To address these limitations, this study employed PC combined with three lignocellulosic model components (cellulose, hemicellulose/xylan, lignin) for synthesizing porous carbon materials through KOH-catalyzed co-pyrolysis. Systematic characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and electrochemical measurements demonstrated that KOH activation effectively removed sulfur impurities while significantly enhancing material porosity and surface area. Among the biomass components, hemicellulose (xylan) exhibited the most pronounced pore-forming effect. The optimized material achieved a specific capacitance of 463.9 F/g at 50 mV/s with over 82% capacitance retention after 5000 cycles, demonstrating exceptional electrochemical stability. This work establishes a novel strategy for transforming petroleum coke into high-performance supercapacitor electrode materials.