Graphene, emerging as one of the most promising class of adsorptive separation carbon material for its high specific surface area and strong surface chemical activity. Biomass especially sustainable biomass as graphene sources shows great potential at large scales under energy shortage era. In this paper, a kind of subtropical macroalgae (Sargassum Horneri, S.H.) was selected as the precursor, and a facile synthesis method based on KOH activation was used to prepare graphene. A continuous monitoring on the formation of graphene and a systematic investigation into biomass precursor were performed, paying special attention to parameters including activation temperature, the alkali and carbon ratio, the corresponding pore structure, and surface chemistry variation. Moreover, the CO₂ adsorption properties of porous graphene were tested. The results showed that, S.H. is a kind of ideal graphene precursor. The optimum preparation of porous graphene by KOH activation was the carbonization temperature of 400 °C, the alkali carbon ratio of 4:1 and the activation temperature of 850 °C. The porous graphene displayed high specific surface area (∼1411 m²/g), pore volume (∼1.16 cm³/g), and abundant microporous and mesoporous structures. The as-prepared porous graphene exhibited good CO₂ uptake capacity as 2.78 mmol/g at 30 °C and 1 bar. The CO₂ adsorption rate equations of the graphene were consistent with the intraparticle diffusion model, indicating that the CO₂ adsorption was mainly controlled by the pore structure, and additionally influenced by the chemical functional groups especially N on the surface.

石墨烯因其高比表面积和强大的表面化学活性而成为最有希望的吸附分离碳材料之一。在能源短缺时代，作为石墨烯来源的生物质特别是可持续的生物质显示出巨大的潜力。本文选择一种亚热带大型藻类（Sargassum Horneri，SH）作为前体，并采用一种基于KOH活化的简便合成方法制备石墨烯。进行了连续监测石墨烯的形成和对生物质前体的系统研究，并特别注意了包括活化温度，碱和碳比，相应的孔结构和表面化学变化在内的参数。此外，CO ₂测试了多孔石墨烯的吸附性能。结果表明，SH是一种理想的石墨烯前体。KOH活化制备多孔石墨烯的最佳方法是碳化温度为400°C，碱碳比为4：1，活化温度为850°C。多孔石墨烯显示出高的比表面积（〜1411m ² / g），孔体积（〜1.16cm ³ / g）以及丰富的微孔和中孔结构。所制备的多孔石墨烯在30℃和1巴下表现出良好的CO ₂吸收能力，为2.78mmol / g。石墨烯的CO ₂吸附速率方程与颗粒内扩散模型一致，表明CO ₂ 吸附主要受孔结构控制，另外还受化学官能团特别是表面氮的影响。