Preparation and formation mechanism of biomass-based graphite carbon catalyzed by iron nitrate under a low-temperature condition

Graphite is a widely used industrial material, which experienced a marked shortage caused by the growing demand for electrode anode material and the increased costs for raw material. Graphitic carbon from biomass is a promising approach that will result in low-cost and efficient preparation. Herein, Fe(NO3)(3) was selected as the catalyst for pine sawdust, and the effects of temperature and iron content on the graphitization of biochar were investigated. Additionally, the formation mechanism of the graphitic crystallite structure was explored. Results showed that the formation of pyrolysis gas increased with the increase in the amount of catalyst added or pyrolysis temperature. The change in pyrolysis gas, such as H-2 and CO, was a critical auxiliary factor reflecting the conversion process. As temperature was increased from 600 degrees C to 800 degrees C, the solid products showed high graphitization and low solid yield. Graphite structure mainly formed at 700 degrees C because of the formation of Fe nanoparticles. The increase in the amount of catalyst could provide more reaction sites and promote the contact between Fe and C, showing that amorphous carbon is dissolved on Fe nanoparticles and precipitated into ordered graphitic carbon. On this basis, a mechanism of carbon dissolution-precipitation was proposed to explain the formation of graphite structure, and the whole pyrolysis process included the transformation of the iron element were analyzed.

Automated summary

Graphite is an important industrial material that has experienced a shortage due to increasing demand and rising costs of raw materials. This study explores a low-cost method of preparing graphite using biomass as the carbon source, and investigates the effects of temperature and iron content on the graphitization process. The results show that increasing the amount of catalyst and temperature can enhance the graphitization of the products.