Department of Chemistry, The City College of New York and The Graduate School of CUNY , 160 Convent Avenue, New York, New York 10031, United States.
ACS Appl Mater Interfaces. 2013 Nov 13;5(21):10565-73. doi: 10.1021/am402305u. Epub 2013 Oct 23.
New hybrid cerium modified zirconium based metal-organic frameworks (MOFs) were synthesized. The as-received materials were evaluated as adsorbents of NO2 in either moist or dry conditions. The surface of the initial and exhausted samples was characterized using XRD, SEM-EDX, nitrogen adsorption, thermal analysis, and FTIR. It was found that the addition of Ce(+3) slightly affects the growth of the framework and introduces new features to Zr-MOF. The shapes of the octahedral crystals are changed, and they are interwoven with rod-flake-like sheets. The extent of the interconnection, and thus the extent of the hybrid MOF formation, depends on the Zr to Ce ratio. The alterations in the surface chemistry and texture are reflected in the amount of NO2 adsorbed. The narrow pore channels present in these new materials enhance adsorption in either moist or dry conditions. The amount of NO2 adsorbed on the Ce-doped MOF increases over 25% in dry conditions in comparison with the unmodified MOF. Exposure of Ce-UiO-66 to NO2 results in a development of porosity. Regardless the conditions, the XRD patterns indicate the stability of this new hybrid MOF upon NO2 adsorption. Interactions of NO2 with MOF result in the formation of nitrate and nitrite species associated either with metals or with organic ligands.
新型混合铈改性锆基金属有机骨架（MOFs）被合成。所接收的材料在潮湿或干燥条件下被评估为 NO2 的吸附剂。初始和耗尽样品的表面使用 XRD、SEM-EDX、氮气吸附、热分析和 FTIR 进行了表征。发现添加 Ce(+3) 略微影响了框架的生长，并为 Zr-MOF 引入了新的特征。八面体晶体的形状发生变化，它们与棒片样薄片交织在一起。连接程度，从而是混合 MOF 形成的程度，取决于 Zr 与 Ce 的比例。表面化学和结构的变化反映在吸附的 NO2 量上。这些新材料中存在的窄孔道增强了在潮湿或干燥条件下的吸附。与未改性的 MOF 相比，Ce 掺杂 MOF 在干燥条件下吸附的 NO2 量增加了 25%以上。Ce-UiO-66 暴露于 NO2 会导致多孔性的发展。无论条件如何，XRD 图谱表明这种新型混合 MOF 在吸附 NO2 时的稳定性。NO2 与 MOF 的相互作用导致硝酸盐和亚硝酸盐物种的形成，这些物种与金属或有机配体有关。
