挥发诱导自组装制备多孔Li₄SiO₄材料

An Evaporation Induced Self-Assembly Method to Porous Li₄SiO₄ Materials

摘要: 本文以氢氧化锂(LiOH•H₂O)为锂源、正硅酸乙酯(TEOS)为硅源、去离子水为溶剂、十六烷基三甲基溴化氨(CTAB) + 聚丙烯酸(PAA)为复合模板剂，采用挥发诱导自组装法(EISA)经高温焙烧制备多孔Li₄SiO₄ 材料。利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对材料的结构特征与表面形貌进行表征，用N₂吸脱附考察材料的孔结构，在热重分析仪(TG)上研究Li₄SiO₄材料高温下的CO₂吸收性能和循环稳定性。实验结果表明，以CTAB + PAA为复合模板剂，60℃溶剂挥发诱导自组装制备的Li₄SiO₄材料在550℃、0.25 bar下5 min内吸收量可达22.5 wt%，且在10 min内达到吸收平衡，平衡吸收量为28.8 wt.％，经5次吸收–解吸后仍保持初始吸收性能，显示了良好的循环稳定性。

Abstract: A solvent evaporation induced self-assembly (EISA) method followed by calcination was employed to prepare porous Li₄SiO₄ materials by using LiOH•H₂O, TEOS, deionized water, and CTAB + PAA as lithium source, silicon source, solvent, and composite template, respectively. X-ray powder dif-fraction (XRD) and scanning electron microscope (SEM) were applied to characterize the structure and morphology of the as-prepared Li₄SiO₄ materials. The pore structures of the Li₄SiO₄ materials were investigated by the N₂ adsorption-desorption analysis. CO₂ uptakes and recycle stability of the prepared Li4SiO4 materials were investigated on a thermogravity (TG) analyzer. The sample synthesized by the EISA method at 60˚C displays CO₂ uptakes up to 22.5 wt% within 5 min. Addi-tionally, an absorption equilibrium of 28.8 wt% can be available within 10 min at 550˚C and a CO₂ partial pressure of 0.25 bar. After five absorption-desorption cycles, the Li₄SiO₄ material keeps its original CO₂ absorption properties, indicating a good cycle stability.