Controllable synthesis,characterization and catalytic performance of a divacant Keggin-type tungstosilicate dimer-estertin derivative  

Keggin型钨硅酸盐二聚体酯锡衍生物的可控合成、表征及催化性能

作　　者：ZHU Haotian ZHANG Ranran LI Mengxuan SUN Yang SU Fang ZHANG Lancui 朱浩天;张冉冉;李孟璇;孙杨;苏芳;张澜萃(辽宁师范大学化学化工学院,辽宁大连116029)

机构地区：[1]School of Chemistry and Chemical Engineering,Liaoning Normal University,Dalian 116029,China

出　　处：《分子科学学报》2024年第5期462-470,共9页Journal of Molecular Science

基　　金：financially supported by the National Natural Science Foundation of China (21671091 and 21503103);the Startup Project of Doctor Scientific Research from Liaoning Normal University (2023BSL017)

摘　　要：A lacunary Keggin-type tungstosilicate dimer-estertin derivative,(C(NH_(2))_(3))_(7)H_(3.5)[(K⊂Ni H_(2)O)_(2)(SnCH_(2)CH_(2)COO)((Ni(H_(2)O))_(0.75)(WO)_(0.25))(Si_(2)W_(18)O_(67))]·6H_(2)O(abbreviated as Si_(2)W_(18)-Ni-SnRCOO,R=CH_(2)CH_(2)),was synthesized by using the conventional aqueous solution method,and characterized by a series of physical and spectral methods.Single crystal X-ray structural analysis revealed that the polyoxometalate(POM)was a dimeric tungstosilicate-based organic-inorganic hybrid compound,which contained two Ni ions and a cyclic carboxyltin group(SnRCOO).Unexpectedly,the carboxyl-oxygen atom of SnRCOO acted as a bridging oxygen atom belonged to the POM skeleton and connected to NiO_(6)octahedron.The thermal and photocatalytic activities of Si_(2)W_(18)-Ni-SnRCOO were studied.As a homogeneous catalyst,the conversion of cyclohexanol to cyclohexanone was as high as 98%,and the degradation efficiency of 20 mg·L^(-1)RhB reached 88%.The experimental results showed that the introduction of the carboxyethyltin group significantly enhanced the catalytic activity of this type of POM-based catalyst.Additionally,the composite of Si_(2)W_(18)-Ni-SnRCOO and TiO_(2) enabled the catalyst to be recycled,and the photocatalytic efficiency of Si_(2)W_(18)-Ni-SnRCOO/TiO_(2) remained almost unchanged after five cycles.采用常规水溶液法合成了一种缺位Keggin型钨硅酸盐二聚体酯锡衍生物(C(NH_(2))_(3))_(7)H_(3.5)[K⊂Ni(H_(2)O)_(2)(SnCH_(2)CH_(2)COO)((Ni(H_(2)O))_(0.75)(WO)_(0.25))(Si_(2)W_(18)O_(67))]·6H_(2)O(简写为Si_(2)W_(18)-Ni-SnRCOO,R=CH_(2)CH_(2)),并通过一系列物理和光谱方法进行了表征。单晶X射线结构分析表明,这种多金属氧酸盐(POM)是一种二聚钨硅酸盐基有机-无机杂化化合物,含有Ni离子和环状羧基锡(SnRCOO)基团。出乎意料的是,SnRCOO的羧基O原子充当了POM骨架与NiO_(6)八面体之间的桥O原子。并研究了Si_(2)W_(18)-Ni-SnRCOO的热催化活性和光催化活性,作为均相催化剂,其催化环己醇氧化为环己酮的转化率高达98%;对20mg·L^(-1)罗丹明B(RhB)的降解效率达到88%。实验结果表明,引入羧乙基锡基团显著提高了这种POM基催化剂的催化活性。此外,Si_(2)W_(18)-Ni-SnRCOO与TiO_(2)复合使催化剂能够回收利用,其光催化效率在五次循环后几乎保持不变。

关 键 词：POLYOXOMETALATE tungstosilicate-estertin derivative crystal structure oxidation catalysis PHOTOCATALYSIS 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]