Low-temperature graphitization of carbon foam using nickel-based catalysts for enhanced thermal conductivity: application in the pyrolysis of oil-rich coal

Carbon foam is a material with wide application, whereas it is still a challenge whether the catalytic graphitization process of carbon foam can enhance the performance of the final carbon foam material while reducing energy consumption. In this study, a comparative evaluation was performed on the catalytic effects of nickel, iron, and boron catalysts on the graphitization of carbon foam. Subsequently, the influence of different catalyst loading levels and graphitization temperatures on the thermal conductivity of graphitized carbon foam was investigated. The carbon foam materials were analyzed using X-ray Diffraction (XRD) and Raman spectroscopy, while their thermal conductivity properties were characterized using a thermal conductivity meter. The oil yield from the pyrolysis of rich oil shale was also used to evaluate the thermal performance of carbon foam materials. The results revealed that, compared to Fe and Be, Ni was found to be more suitable for graphitization among the tested catalysts. Furthermore, the optimal conditions for achieving the best graphitization effect on carbon foam material were determined to be a nickel nitrate (Ni(NO₃)₂·6H₂O) concentration of 2 mol/L and a graphitization temperature of 1000 °C. The thermal conductivity of the graphitized carbon foam material prepared under this condition was increased by 25.3% from 0.2016 W·m⁻¹·K⁻¹ to 0.2526 W·m⁻¹·K⁻¹, and the tar yield was increased by 46.4% when it was applied to oil-rich coal pyrolysis. This preparation process not only saves energy but also yields graphitized carbon materials with excellent thermal conductivity, holding promising prospects for a wide range of applications.

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