Low-temperature organic solvent-based synthesis of amorphous porous carbon nanoparticles with high specific surface area at ambient atmosphere

The conventional synthesis of porous carbon materials is primarily relied on the activation and template process. This work successfully develops a one-step method for preparing amorphous porous carbon nanoparticles (APCNs) with a high specific surface area (SSA) in organic solvents under ambient atmosphere. The APCNs are formed mainly by the reaction of ferrocene with ammonium chloride at only 180 °C for 1 h in different solvents. Several ferrocene derivatives and KOH activation are also utilized to improve the textural properties of the APCNs. It is found that the high solubility of (C₅H₅)₂Fe and FeCl₃·6H₂O in a solvent is the most essential factor associated with the decrease of carbon nanoparticle size. The smaller the nanoparticle size, the larger the SSA of APCNs. The APCNs prepared in phenoxyethanol have a median size of 32.74 nm, exhibiting an SSA of 689 m²/g. The high solubility of NH₄Cl can also contribute to reducing the nanoparticle size. The binary solvent consisting of phenoxyethanol and glycol has an excellent solubility for (C₅H₅)₂Fe, FeCl₃·6H₂O, and NH₄Cl, in which the prepared APCNs have a median size 11.48 nm and a higher SSA of 936 m²/g. Besides, the benzoyl substituted group on the cyclopentadiene can facilitate formation of small mesopores. The oxygen and nitrogen are in situ doped in the APCNs. Activation is also effective, and the SSA of APCNs reaches a maximum value of 1575 m²/g at a KOH ratio of 2:1. The solvent-based synthesis is unique and competitive in terms of high efficiency and energy conservation.