Non-Supertetrahedral Cluster-Based Crystalline Metal Chalcogenides And Their Photocatalytic Property

In the past 30 years.cluster-based crystalline metal chalcogenides(CCMCs)have been widely used in the fields of photocatalysis,electrocatalysis.photoluminescence,ion exchange,nonlinear optics,gas adsorption,heavy metal and radionuclide removaldue to their porous,semiconductor properties,diverse structures and precisely adjustable compositions.The metal chalcogcnide clusters with different sizes,shapes,compositions and assembly modes are the most important basic building units.which play a significant role in determining the structure and function of CCMCs.More importantly.it is conducive to explore the "structure-property" relationship between structure and performance by using the precise structure and component tunability of clusters.Up to date.the metal chalcogenide clusters assembled in the superlattices of CCMCs are mainly belong to tetrahedrally-shaped Tn supertetrahedral clusters(n means the number of metal layers)and Tn-derivative supertetrahedral clusters,while CCMCs with non-supertetrahedral clusters as building units are rarely documented.Although supertetrahedral clusters play a fundamental role in promoting the development of CCMCs.their well-known structure type and connection modes limit the expandability of more structures and properties of CCMCs.In this thesis,we have obtained two novel non-supertetrahedral CCMCs under solvothermal method and their photocatalytic properties were investigated.The specific research contents of this thesis are as follows:1.New copper-rich open framework chalcogenides and study on their photocatalytic performanceUnder solvothermal condition,we have obtained two new copper-rich open framework chalcogenides(COCs)with 1.5-diazabicyclo[4.3.0]non-5-ene(DBN)as the template.The skeleton units of these two chalcogenides are[(Cu5Sn4InSe14)]4-and[(Cu5Sn4GaSe14)]4-,respectively.[Cu5(SnxM1-x)Se10]clusters are bridged by dimeric[(SnxM1-x)2Se6]in tetrahedral coordination to form a CrB4 type topological structure.which is quite distinguished from the typical COCs with PCU topology.This is also the first time to observe the trivalent metal component in the COCs system.In addition,the photocurrent response characteristics in the infrared range and the photocatalytic degradation activity of methylene blue dye molecule indicate that trivalent main-group metal components can help to regulate the band gap and photoavailability of COCs This study not only enriches the structure of COCs,but also demonstrates their potential application in the field of photocatalysis2.The wheel-shaped gallium-sulfur clusters and their photocatalytic propertiesWe reported a new type of wheel-shaped Ga-S cluster.The obtained cluster consists of 24 Ga atoms and 40 S atoms,which is decorated(not bridged)by pure organic amine to form a double-decker regular ring structure.It is the first time to obtain main-group metal sulfide based on nano-ring cluster with gallium involved,despite several gallium molecular wheels built by Ga atoms bridged by organic OMe and OAc ligands.And it is also the largest regular ring cluster in main-group metal chalcogenides.and contains the largest number of metal atoms among sulfide-based ring cluster up to now.In addition,in order to adjust the band gap of the wheel-shaped chalcogenides and enhance their photocatalytic activity,we successfully introduced the In atom into sulfide-based ring cluster.The experimental results showed that In components enhance the photocurrent response and improve the efficiency of photodegradation dyes and photocatalytic hydrogen productionIn this thesis,the diversity of the basic building units of CCMCs is realized,and the research results enrich the system of non-supertetrahedral cluster-based CCMCs,which provide theoretical guidance for the synthesis and the related performance research of non-supertetrahedral clusters in the future.