▎ 摘　　要

BACKGROUND: Macroalgae biomass as a graphene source shows great potential at large scale in an energy shortage era. To achieve a more moderate and economic graphene synthesis method, porous graphenes were synthesized using Sargassum horneri as precursor, in combination with Fe(NO3)(3) and KOH composite. RESULTS: The addition of 10 wt% Fe(NO3)(3) obviously accelerated KOH activation and decreased KOH loading and reaction temperature. Meanwhile, the graphene synthesized by Fe(NO3)(3)/KOH had better regeneration performance than that activated merely by KOH, even under more moderate thermal condition. The porous graphene displayed high specific surface area (similar to 2311 m(2) g(-1)) and exhibited good CO2 uptake capacity (similar to 4.39 mmol g(-1)) at 30 degrees C and 1 bar. The CO2 adsorption rate equations of the graphene were consistent with the intraparticle diffusion model, indicating that CO2 adsorption was mainly controlled by the pore structure and additionally influenced by the chemical functional groups. CONCLUSION: The present work focuses on the high value-added comprehensive utilization of macroalgae, which not only has important significance for on-scale preparation of bio-originated graphene and CO2 adsorption, but also has positive benefits for macroalgae resource development. (C) 2022 Society of Chemical Industry (SCI).