標題: Synthesis, Characterization, and CO2 Adsorptive Behavior of Mesoporous AlOOH-Supported Layered Hydroxides
作者: Chang, Yen-Po
Chen, Yu-Chun
Chang, Po-Hsueh
Chen, San-Yuan
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: carbon dioxide capture;hydroxides;mesoporous materials;reaction mechanisms;surface chemistry
公開日期: 2012
摘要: A novel CO2 solid sorbent was prepared by synthesizing and modifying AlOOH-supported CaAl layered double hydroxides (CaAl LDHs), which were prepared by using mesoporous alumina (?-Al2O3) and calcium chloride (CaCl2) in a hydrothermal urea reaction. The nanostructured CaAl LDHs with nanosized platelets (330 nm) formed and dispersed inside the crystalline framework of mesoporous AlOOH (boehmite). By calcination of AlOOH-supported LDHs at 700 degrees C, the mesoporous CaAl metal oxides exhibited ordered hexagonal mesoporous arrays or uniform nanotubes with a large surface area of 273 m2?g-1, a narrow pore size distribution of 6.2 nm, and highly crystalline frameworks. The crystal structure of the calcined mesoporous CaAl metal oxides was multiphasic, consisting of CaO/Ca(OH)2, Al2O3, and CaAlO mixed oxides. The mesoporous metal oxides were used as a solid sorbent for CO2 adsorption at high temperatures and displayed a maximum CO2 capture capacity (approximate to 45 wt?%) of the sorbent at 650 degrees C. Furthermore, it was demonstrated that the mesoporous CaAl oxides showed a more rapid adsorption rate (for 12 min) and longer cycle life (weight change retention: 80?% for 30 cycles) of the sorbent because of the greater surface area and increased number of activated sites in the mesostructures. A simple model for the formation mechanism of mesoporous metal oxides is tentatively proposed to account for the synergetic effect of CaAl LDHs on the adsorption of CO2 at high temperature.
URI: http://hdl.handle.net/11536/16557
ISSN: 1864-5631
期刊: CHEMSUSCHEM
Volume: 5
Issue: 7
結束頁: 1249
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