Homogeneous-pore-creation in pitch-based carbon fibers by extraction-activation and their application as supports for catalytic hydrogenation

Abstract

The homogeneous pore distribution and suitable pore size in porous carbons play a crucial role in enhancing the catalytic performance of carbon-supported catalysts. The strategic design and controllable preparation of porous carbon supports for heterogeneous catalysis still remain a challenge. This study employs a novel method of combining toluene Soxhlet extraction and steam activation to construct homogeneous pores in pitch-based carbon fibers (PCFs) for catalytic applications. The results show that toluene extraction creates abundant micropores in isotropic pitch fibers to form the primary pores, while subsequent steam activation further increases the porosity and pore volume of PCFs. Compared to single methods of toluene extraction or steam activation, this combined approach demonstrates a significant advantage in the design and creation of homogeneous micropores (0.5 ∼ 2.0 nm) in PCFs with a high specific surface area of 1169.0 m²/g. 10 wt% nanoscale Ni particles supported on the as-prepared porous PCFs exhibit exceptional catalytic performance in the hydrogenation of nitrobenzene to aniline. Under mild reaction conditions of 120 °C and 2 h, the conversion of nitrobenzene and the selectivity of aniline approach 96.4 % and 100 %, respectively, superior to those of reference Ni-based catalysts. This work provides a promising strategy for creating homogeneous micropores in PCFs, which are suitable as catalyst supports to achieve the catalytic synthesis of high value-added chemicals.