Abraha Yuel W, Tsai Chih-Wei, Niemantsverdriet J W Hans, Langner Ernst H G
Department of Chemistry, University of the Free State, Nelson Mandela Drive, P.O. Box 339, Bloemfontein 9300, South Africa.
Department of Physics, University of the Free State, Nelson Mandela Drive, P.O. Box 339, Bloemfontein 9300, South Africa.
ACS Omega. 2021 Aug 18;6(34):21850-21860. doi: 10.1021/acsomega.1c01130. eCollection 2021 Aug 31.
Zeolitic imidazolate frameworks, like ZIF-8 and related structures, have shown great potential for the capture of carbon dioxide. Modifying their structure by exchanging part of the constituent organic ligands is a proven method for enhancing the capacity to absorb CO. In this work, we performed solvent-assisted ligand exchange (SALE) on nanosized ZIF-8 (nZIF-8) with a series of functionalized imidazole derivatives (exchange percentages, after 24 h): 2-bromoimidazole (19%), 2-chloroimidazole (29%), 2-trifluoromethylbenzimidazole (4%), 2-mercaptobenzimidazole (4%), and 2-nitroimidazole (54%). The sodalite topology and porosity of nZIF-8 were maintained with all SALE modifications. Low-pressure CO adsorption of nZIF-8 (38.5 cm g) at STP was appreciably enhanced with all mixed-linker SALE products. Using halogenated (-Cl, -Br, and -CF) imidazole derivatives in a 24 h SALE treatment resulted in increases between 11 and 22% in CO adsorption, while the thiol (-SH)- and nitro (-NO)-functionalized SALE products led to 32 and 100% increases in CO uptakes, respectively. These CO uptakes were further optimized by varying the SALE treatment time. The SHbIm- and NOIm-exchanged SALE products of nZIF-8 show 87 and 98 cm g of CO uptakes after 60 and 120 h of SALE, respectively. These are record high CO adsorptions for all reported ZIF derivatives at low-pressure conditions.
沸石咪唑酯骨架材料，如ZIF-8及相关结构，已显示出捕获二氧化碳的巨大潜力。通过交换部分组成有机配体来修饰其结构是一种提高吸收CO能力的成熟方法。在这项工作中，我们用一系列功能化咪唑衍生物对纳米级ZIF-8（nZIF-8）进行了溶剂辅助配体交换（SALE）（24小时后的交换百分比）：2-溴咪唑（19%）、2-氯咪唑（29%）、2-三氟甲基苯并咪唑（4%）、2-巯基苯并咪唑（4%）和2-硝基咪唑（54%）。所有SALE修饰均保持了nZIF-8的方钠石拓扑结构和孔隙率。所有混合连接体SALE产物均显著提高了nZIF-8在标准温度和压力下的低压CO吸附量（38.5 cm³/g）。在24小时的SALE处理中使用卤化（-Cl、-Br和-CF₃）咪唑衍生物，CO吸附量增加了11%至22%，而硫醇（-SH）和硝基（-NO₂）功能化的SALE产物使CO吸收量分别增加了32%和100%。通过改变SALE处理时间，这些CO吸收量得到了进一步优化。nZIF-8的SHbIm-和NOIm-交换SALE产物在SALE 60小时和120小时后，CO吸收量分别为87和98 cm³/g。这些是所有报道的ZIF衍生物在低压条件下的创纪录高CO吸附量。
