Preparation of N/O self-doped and hierarchical porous carbon from co-pyrolysis of porphyra and corn stalk for Cl-VOC efficient adsorption

Carbon materials derived from single biomass feedstock typically have serious defects such as low porosity and poor distribution of functional groups. In this work, a series of porous carbons with different mass ratios of porphyra and corn stalk (7:3, 1:1, and 3:7) were prepared by ingeniously utilizing co-pyrolysis coupled with KOH activation. The prepared porous carbon samples were characterized by N 2 adsorption/desorption isotherms, Field emission scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Thermo-gravimetric analysis. Results showed that the prepared CPPC73 possessed excellent adsorbent properties, including high specific surface area (2719 m 2 /g), large pore volume (1.225 cm 3 /g), hierarchical porous structure, and optimal distribution of N-containing functional groups. Chlorobenzene (CB) dynamic adsorption experiments indicated that CPPC73 had higher adsorption performance (1134 mg/g) than unmodified POPC (795 mg/g). A combination of density functional theory (DFT) calculations, correlation analysis, and Grand canonical Monte Carlo (GCMC) calculations was performed to clarify the CB adsorption mechanism. Correlation analysis and GCMC calculations confirmed that pores in the range of 0.7–2.0 nm were the best adsorption sites for CB. Furthermore, DFT calculations indicated that N/O-containing functional groups on the carbon surface enhanced the interaction between porous carbon and CB, especially the pyrrolic-N. This work offers a new strategy to convert waste seaweed into a high-performance adsorbent for Cl-VOCs removal.