Self-Assembly Of Two Kinds Of Surfactants Encapsulated Polyoxometalates

Polyoxometalates(POMs)have obtained widespread application due to their advantageous properties.During self-assembly,the interaction between building blocks could exhibit novel properties and new function.Self-assembly of POMs is a new field with great challenge.Two challenging issues need to be dealed with now: 1.Most of the researches just used one kind of surfactants encapsulated POMs as building block.2.Previous studies focused on obtaining new structures of assemblies and ignored the application of assemblies.Therefore,two kinds of surfactants encapsulated POMs is of great importance for building assemblies with novel structures,exploring the mechanism of self-assembly.Based on above,this dissertation studied the behavior and mechanism of self-assembly,obtained novel structures,and explored their application.The main points of this dissertation can be summarized as follows:First,hexadecyl trimethyl ammonium bromide and tetrabutyl ammonium bromide were used to encapsulate the POMs with characteristic crystal structure of Wells-Dawson.A new method based two kinds of surfactants was built.Then a supramolecular gel formed through the self-assembly of surfactant encapsulated Wells-Dawson POMs which occurred in the butanone and ethyl acetate.And this gel was made up of nanorolls.When the ester was substituted by unsaturated ester,the gel could be polymerized and formed hybrid materials with photochromic property.Therefore,supramolecular gel is a good platform for POMs processing.Second,the monolayer superlattice was obtained from self-assembly of surfactant-encapsulated POMs through the evaporation of solvents.To make the superlattice more processible,self-assembly on graphene oxide(GO)been carried out.The superlattice@GO can be a promising hydrogen peroxide sensor.Additionally,the superlattice@GO has also shown enhanced photoelectrochemical properties.More important,all kinds of Wells-Dawson POMs could be used to form the monolayer superlattice.These findings mayprovide a promising avenue to integrating monolayer superlattice with GO which will show more new properties.The third part is about single-atom catalyst.Through self-assembly,a new kind of single-atom catalyst based palladium substituted POMs(Pd-POM)was found.And these surfactants encapsulated Pd-POM could assemble into nanorolls and hollow spindles.At room temperature,both of these assmblies could act as high-performance catalysts in the Suzuki-Miyaura coupling reaction.The coupling reaction was completed in 30 min.At the same time,the nanoroll was further used to catalyze semi-hydrogenation of alkynes with higer yield and stereo-selectivity.This study are expected to bring new insights into the development of single-atom catalyst.And when POMs were used as tungsten or molybdenum precursors,the Mo S2,WS2 and Mo Se2 nanostructures have been synthesized at a lower temperature.This dissertation focuses on two kinds of surfactants encapsulated POMs.A series of assemblies with new structures have been obtained through different methods(self-assembly in solvents or the evaporation induced self-assembly).And the application of the assemblies has been studied.On this basis,we explored the mechanism of self-assembly and structure-property relationship.