Mechanistic insights into phenol-ammonia synergy for optimizing phenolic porous carbon synthesis and pore formation

While phenolic porous carbons (PPCs) are commonly synthesized from single phenols, the impact of mixed phenols and ammonia on pore structure formation has yet to be fully elucidated. In this study, phenolic and ammonia components from semi-coking wastewater were used to prepare high-performance porous carbon, activated by sodium-based agents. Response surface methodology (RSM) identified optimal conditions—Na 2 CO 3 -to-resin ratio of 2.13:1, carbonization temperature of 784 °C, and activation time of 1.52 h—yielding an iodine adsorption capacity of 1046.36 mg/g. XPS analysis showed that Na 2 CO 3 activation resulted in higher retention of nitrogen, oxygen, and sulfur compared to KOH activation. This is attributed to the gentler etching effect of Na 2 CO 3 , which facilitated the formation of larger mesopores and macropores. Thermal and kinetic analysis revealed lower activation energies for Na 2 CO 3 -activated resins, especially when mixed phenols and ammonia were used as precursors. SEM and BET analysis confirmed the presence of a hierarchical pore structure. Additionally, ammonia was found to enhance pore formation, resulting in smoother and more uniform pores. These findings demonstrate the feasibility of using semi-coking wastewater as a precursor for producing sustainable porous carbon materials, offering potential applications in both environmental remediation and energy storage.