铜箔上原位合成NENU-n系列多酸基MOFs的通用策略

NENU-n系列多酸基金属有机框架杂化物(POM@MOFs)是将一系列性能优异的Keggin型杂多酸封装到Cu₃(BTC)₂框架中形成的, 在催化和质子传导等领域展示出优异的性能. 本文在前期工作的基础上发展了一种在铜箔上原位合成POM@MOFs的新方法, 即向反应液中通入氧气, 利用酸性条件下氧气能将Cu⁰氧化为Cu²⁺的特性为金属有机框架的生长提供铜离子源, 使氧化能力较弱的Keggin型钨系杂多酸也可在铜基底上原位合成纯相NENU-n系列杂化物. 该方法可在室温条件下进行, 简便、 快速且原子经济性高. 同时发现在不添加任何调节剂的条件下, 利用该方法能生成形貌可控的POM@MOFs, 其形貌依赖于杂多酸阴离子所带的电荷. 电荷高的杂多阴离子可以得到立方体形貌, 而电荷低的杂多阴离子得到八面体形貌. 利用合成的材料对芥子气模拟物2-氯乙基乙基硫醚(CEES)的催化氧化反应进行了研究, 结果表明暴露活性位点更多的立方体形貌的NENU-40K₅BW₁₂O₄₀/Cu₃(BTC)₂]展现出更优异的催化活性, 10 min内即可将2-氯乙基乙基硫醚完全转化为无毒的亚砜.

General Strategy for In situ Synthesis of NENU-n Series Polyoxometalate-based MOFs on Copper Foil

The NENU-n series polyoxometalate-based metal-organic framework（POM@MOFs） are formed by encapsulating a series of excellent Keggin type polyoxometalates into Cu₃（BTC）₂ framework， showing excellent performance in the fields of catalysis and proton conduction. In this work， a new method of in situ synthesis of POM@MOFs on copper foil was developed on the basis of the previous work， that is， oxygen was added into the reaction solution， and the oxygen could oxidize Cu⁰ to Cu²⁺ under acidic conditions to provide copper ion source for the growth of the metal-organic framework. Thus， even though the oxidation capacity of Keggin tungsten polyoxometalates is weak， pure phase products of NENU-n series hybrids can also be synthesized in situ on copper substrates. The method is simple， rapid and high atomic economy at room temperature. Moreover， we found that POM@MOFs with controllable morphology can be generated by using this method without adding any regulator， and its morphology depends on the charge of heteropoly acid anions. The heteropoly anion with high charge can obtain the cubic morphology， while the heteropoly anion with low charge can obtain the octahedral shape. Catalytic oxidation of simulated mustard gas （2-chloroethylethyl sulfide， CEES） was studied by using the synthesized materials. The results showed that the NENU-40［K₅BW₁₂O₄₀/Cu₃（BTC）₂］ with cubic morphology exposed more active sites and showed a better catalytic activity. CEES can be completely converted to non-toxic CEESO within 10 min.