Alkali metal cation doping of metal-organic framework for enhancing carbon dioxide adsorption capacity

• Published in: Journal of energy chemistry Vol. 23; no. 4; pp. 468 - 474
• Main Authors: Cao, Yan, Zhao, Yunxia, Song, Fujiao, Zhong, Qin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2014; Elsevier
• Subjects: adsorption-desorption cycles; alkali metals cation doping; carbon dioxide adsorption; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; HKUST-1; metal-organic framework; Porous materials; Solid-gas interface; Surface physical chemistry; X射线粉末衍射; 吸附能力; 吸附量; 碱金属; 离子掺杂; 表面化学; 骨架; 高二氧化碳; adsorption-desorption cycles; carbon dioxide adsorption; alkali metals cation doping; HKUST-1; metal-organic framework; Carbon dioxide; Doping; Adsorption capacity; Copper Complexes; Porous material; Texture; Surface structure; Characterization; Surface properties; Adsorbent; Metal organic framework; Scanning electron microscopy; Thermogravimetry; Doped materials; CO2 sequestration; Transition metal Complexes; Alkali metal; X ray diffraction; Gas solid adsorption; Inorganic cation; Regeneration; Morphology; Carboxylate; Thermal analysis; Surface area
• ISSN: 2095-4956
• DOI: 10.1016/s2095-4956(14)60173-x

Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.