More and more studies have shown that zeolitic imidazolate framework (ZIF) materials exhibit very high thermal stability, but poor aqueous stability, that limits their practical application. In this work, leaf-shaped ZIF-67 on the surface of foam nickel (namely as ZIF-L-Co/NF) is selected to deeply investigate the mechanism of water stability. The related reaction process of ZIF-L-Co/NF in water is proposed for the first time and demonstrated based on a series of characterizations. The results show that ZIF-L-Co/NF lost its skeleton after only 1 h in water, and completely converted into cobalt hydroxide (Co(OH)) after 24 h. The reaction process is proved to be invertible via designed experiments. Considering invertible reaction, two strategies are proposed to improve the water stability of ZIF-L-Co, by (1) introducing second metal center Zn and (2) adding extra 2-methylimidazole (Hmim) to push the reaction process in reverse. Based on the above improving strategies, bimetallic ZIF-L-CoZn/NF(2:1) prepared by introducing the second metal Zn is applied as electrochemical sensor towards glucose, and exhibits high sensing performance with good sensitivity, selectivity, and wide detection range as glucose sensor. Experimental results demonstrate its excellent aqueous stability. This work provides a totally new viewpoint for the application of ZIF materials in aqueous conditions and perfects the characteristics of ZIF family.

中文翻译：

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研究并提高电化学葡萄糖传感器用 ZIF-L-Co 的水稳定性

越来越多的研究表明，沸石咪唑骨架（ZIF）材料表现出很高的热稳定性，但水稳定性较差，限制了其实际应用。本工作选择泡沫镍表面的叶状ZIF-67（即ZIF-L-Co/NF）来深入研究水稳定性的机理。首次提出了ZIF-L-Co/NF在水中的相关反应过程，并基于一系列表征进行了论证。结果表明，ZIF-L-Co/NF在水中仅1小时后就失去了骨架，并在24小时后完全转化为氢氧化钴(Co(OH))。通过设计实验证明该反应过程是可逆的。考虑到可逆反应，提出了两种策略来提高ZIF-L-Co的水稳定性，即(1)引入第二金属中心Zn和(2)添加额外的2-甲基咪唑(Hmim)以逆向推动反应过程。基于上述改进策略，引入第二金属Zn制备的双金属ZIF-L-CoZn/NF(2:1)作为葡萄糖电化学传感器，表现出良好的灵敏度、选择性和较宽的检测范围的高传感性能。作为葡萄糖传感器。实验结果证明其优异的水稳定性。该工作为ZIF材料在水性条件下的应用提供了全新的视角，完善了ZIF家族的特性。