Integrating TG–FTIR analysis and predictive modeling to elucidate phenolic enrichment in biomass pyrolysis over transition-metal/g-C3N4 catalysts

This study investigated the catalytic pyrolysis of pine sawdust over transition-metal-modified g-C 3 N 4 catalysts (Ni/g-C 3 N 4 , Zn/g-C 3 N 4 , and Co/g-C 3 N 4 ) to enhance phenolic selectivity and elucidate metal–support synergistic effects. Among these catalysts, Co/g-C 3 N 4 exhibited the best performance in enhancing the relative content of phenolic compounds. Compared with non-catalytic pyrolysis at 550 ℃, the phenolic content increased by 24.66%. In addition, the results indicated that a CO 2 atmosphere negatively affected phenolic formation. The temperature-programmed TG-FTIR and evolved-gas analyses revealed that the presence of the Co/g-C 3 N 4 catalyst could promote the formation of CO and limit the generation of CH 4 and C 2 -C 3 hydrocarbons during the catalytic pyrolysis process. The related mechanism analysis showed that the interaction between Co 2 + /Co 3+ species on g-C 3 N 4 and Lewis-basic N sites enabled an interfacial synergistic effect for the selective formation of catechol and methyl-catechol. Furthermore, the exploratory multi-output regression analysis further verified that catalyst type primarily governed phenolic enrichment, whereas temperature mainly influenced syngas formation. Overall, this study provides a deeper understanding of the reaction pathways for the selective generation of phenolic compounds in biomass catalytic pyrolysis, and offers a practical approach for the integration of experimental analysis and data-driven methods.