A template-free, thermal decomposition method to synthesize mesoporous MgO with a nanocrystalline framework and its application in carbon dioxide adsorption
A template-free, thermal decomposition method to synthesize mesoporous MgO with a nanocrystalline framework and its application in carbon dioxide adsorption
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DOI：
10.1039/c0jm01261k
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发表时间：
2010-01-01
影响因子：
--
通讯作者：
Grassian, Vicki H.
中科院分区：
文献类型：
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作者：
Bian, Shao-Wei;Baltrusaitis, Jonas;Grassian, Vicki H.
碱土金属氧化物是二氧化碳储存的重要材料。本文提出了一种无模板剂、无水醋酸镁热分解合成介孔氧化镁的方法。采用扫描电子显微镜（SEM）、高分辨透射电子显微镜（HRTEM）、粉末X射线衍射（XRD）和氮吸附分析等技术和方法对介孔MgO样品的晶相、粒径、孔径和表面积进行了表征。结果表明，以无水醋酸镁为原料制备的介孔MgO具有较高的比表面积（120-136 m2·g-1）和较窄的孔径分布（3-4 nm）。孔结构由具有颗粒间连接的小的初级MgO纳米颗粒聚集体组成。采用原位透射傅里叶变换红外光谱研究了CO2在介孔MgO上的吸附。这种光谱研究表明，介孔MgO表现出增强的CO2吸附能力相对于市售的MgO纳米粒子。这一差异主要归因于表面积的增加。中孔和商业MgO样品之间观察到表面碳酸盐/碳酸氢盐形态的差异，并与较小的纳米颗粒的结构差异有关。
Alkaline earth-based oxides are important materials in the storage of carbon dioxide. Here we present a template-free synthesis method for mesoporous magnesium oxide (MgO) via the thermal decomposition of anhydrous magnesium acetate. Characterization of the crystalline phase, particle size, pore size and surface area for mesoporous MgO samples was accomplished using a variety of techniques and methods including scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), and nitrogen adsorption analysis. The results showed that mesoporous MgO prepared from anhydrous magnesium acetate had a high surface area in the range of 120-136 m(2) g(1) and a narrow pore size distribution in the range of 3-4 nm. The pore structure was composed of small primary MgO nanoparticle aggregates with interparticle connections. In situ transmission FTIR spectroscopy was used to investigate CO2 adsorption on mesoporous MgO. This spectroscopic investigation showed that mesoporous MgO exhibited enhanced CO2 adsorption capacity relative to commercially available MgO nanoparticles. This difference was attributed mainly to an increase in surface area. Differences in surface carbonate/bicarbonate speciation were observed between the mesoporous and commercial MgO samples and were related to structural differences for the smaller nanoparticles.