| Photocatalysis,as a potential technology to deal with energy and environmental challenges,has attracted widespread attention from scientists all over the world.With the rapid development of this research orientation,scientists have a great interest in developing excellent photocatalytic materials.As a new type of composite photocatalytic material,the ZnIn2S4 has shown a great potential as the heterogeneous photocatalyst in the application of organic synthesis.Considering that the ZnIn2S4 composite material has the advantages of narrow band gap and high chemical stability,it has been widely used in the fields of hydrogen evolution,carbon dioxide reduction and organic pollutant degradation.However,there are still few applications in promoting the photocatalytic synthesis.Therefore,the study on the ZnIn2S4 catalyzed oxidation/dehydrogenation coupling reaction of organic small molecules under visible light is of important scientific value and industrial prospects.In this thesis,the preparation method of indium zinc sulfide catalytic materials was researched in detail,and its photocatalytic performance on the visible light catalyzed oxidative coupling process of benzylamine and the dehydrogenation coupling reaction of furfuryl alcohol was systematically investigated.1.Under blue light irradiation,the selective formation of C=N and C-N bonds through photocatalytic coupling reaction of benzylamine was achieved at room temperature.Therein,a series of metal sulfide materials were successfully prepared and further employed in the photocatalytic selective conversion of different amine compounds.The experimental results indicated that,with ZnIn2S4 as the catalyst,the selective formation of C=N bond or C-N bond can be effectively regulated by exchanging the gas atmosphere.As a result,the main product is N-benzylidene benzylamine when the photocatalytic benzylamine conversion was performed under the oxygen atmosphere,in which the selectivity of product is as high as 99%;while,under the argon atmosphere,the obtained reaction product is mainly triphenylamine where the conversion of benzyl amine can reach 99%under the optimal conditions.In addition,the photocatalytic oxidative coupling reaction of different amine compounds was also researched in detail.The yield of the main products ranged from 65 to 99%.Furthermore,based on the control experiment data and characterization results,the reaction mechanism of the conversion of benzylamine to form C=N and C-N bonds under visible light irradiation was proposed.2.The selective dehydrogenative coupling reaction of furfuryl alcohol is also further studied with the composite metal sulfide catalysts modified by different surfactants and the indium zinc sulfides including various zinc/indium ratio during preparation.The results showed that the synthesis method of ZnIn2S4 has a significant impact on its photocatalytic performance.The ZnIn2S4-P catalyst synthesized using the polyethylene glycol（PEG）as the surfactant provided the excellent catalytic activity on the selective conversion of furfuryl alcohol.Therein,an 87.2%conversion in a 75.6%selectivity of hydro furoin was obtained at room temperature under visible light.In particular,ZnIn2S4-P catalyst can prolong the effective life of electron hole pairs to more than 7 ns which is very helpful for the formation of a large amount of furfuryl alcohol radicals.Finally,according to the results of control experiments and catalyst characterization,a possible catalytic mechanism for the dehydrogenative coupling reaction of furfuryl alcohol is proposed.Compared with the industrial 1,2-diol preparation method,the selective coupling process of monohydric alcohol under the light irradiation has several advantages of relatively mild conditions,simple operation and the high atom economy.At the same time,it also provides a promising and environmentally friendly approach for the effective construction of C-C single bond in the chemical synthesis field. |
