Influence of Alkali Metals (Na, K, and Cs) on CO2 Adsorption by Layered Double Oxides Supported on Graphene Oxide

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• 作者：Diana Iruretagoyena ; Xiaowen Huang ; Milo S. P. Shaffer ; David Chadwick
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：54
• 期：46
• 页码：11610-11618
• 全文大小：399K
• ISSN：1520-5045

文摘

The CO₂ adsorption capacities, isotherms, and thermal stability of sodium, potassium, and cesium impregnated layered double oxides (LDOs) supported on graphene oxide (GO) are reported. Alkali cations were found to modify the distribution and density of chemisorption sites resulting in higher CO₂ adsorption capacities at 573 K (0.56鈥?.69 molCO₂/kg) compared to the unpromoted adsorbents (0.29 molCO₂/kg) (LDO and LDO/GO hybrids). The improved thermal stability imparted by incorporation of GO in the LDO was not compromised by the addition of any of the alkali species. Potassium produced the most marked enhancement in CO₂ capacity (0.47 molCO₂/mol alkali) due to its relatively strong Lewis basicity and even distribution on the surface of the adsorbents. Cesium was found to have a tendency to agglomerate that reduced the effectiveness of promotion. The CO₂ adsorption equilibrium of the fresh calcined materials is described by the Freundlich model. After thermal adsorption鈥揹esorption cycles the isotherms fit closer to the Langmuir isotherm.