Description:
Graphite is a widely used industrial material, which experienced a marked shortage due to the growing demand for electrode anode material and the increased costs for raw material. Synthesizing the biomass-based graphitic carbon from biomass by one-pot slow pyrolysis is a promising approach to realizing low-cost, sustainable, and efficient preparation. In this study, Fe(NO3)3 was selected as the catalyst, the effects of temperature and iron content on the graphitization of biochar were investigated. Additionally, the formation mechanism of the graphitic crystallite structure of biochar was explored. Results showed that the formation of pyrolysis gas increased with the increase of catalyst dosage or pyrolysis temperature. The change of reductive gas, such as H2 and CO, was a critical auxiliary factor reflecting the conversion process. Also, under the condition of increasing pyrolysis temperature, the solid products showed high graphitization and low solid yield. Hence, increasing the amount of catalyst could provide more reaction sites and contribute to the formation of the graphitic structure. On this basis, the graphitization mechanism of biomass char and the transformation process of the iron element during the pyrolysis were analyzed. A possible mechanism of “carbon dissolution-precipitation” was proposed to explain the experimental phenomenon. Fe(III) was first converted to Fe(II) in the reaction process and then converted to Fe nanoparticles