Synthesis And Photocatalytic Performance Of Reduced Graphene Oxide-semiconductor In₂S₃ Composites

In rencent years,reduced graphene oxide(RGO)-based semiconductor composites have been achieving ever-increasing attention in photocatalysis area.As a two-dimensional(2D)conductive platform,RGO can accept and transport the photogenerated electrons from the semiconductor.Therefore,it is crucial to efficiently utilize the electronic conductivity of RGO to improve the photocatalytic performance of RGO-based semiconductor composites.Since the transfer of photoinduced electrons occurs along the interface between RGO and the semiconductor,synthesis of RGO-based semiconductor composites with good interfacial contact is a key factor to improve the photoactivity of the composites.On the other hand,on the premise of the good interfacial contact,how to engineer the interfacial composition to optimize the charge carrier transfer pathway across the interface between RGO and the semiconductor is also of great importance.In this dissertation,we have firstly prepared hierarchical In2S3-RGO composites in virtue of the "structure directing" role of graphene oxide(GO)by an in-situ hydrothermal method.And then with the addition of a small amount of palladium(Pd)nanoparticles,ternary In2S3-RGO-Pd composites have been obtained by a facile wet chemistry method.Selective oxidation of a range of alcohols under visible light irradiation has been taken as the probe reactions to evaluate the photocatalytic performance of the as-prepared samples.Relevant characterizations including X-ray diffraction(XRD),UV-vis diffuse reflectance spectra(DRS),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),FT-IR,electrochemical analysis,and photoluminescence spectra(PL)have been carried out to observe the properties of the samples.The primary results and conclusions derived from the present research are as follows:1.Hierarchical In2S3-RGO composites featuring good interfacial contact between RGO and In2S3 display higher photoactivity toward selective oxidation of a range of alcohols upon visible light irradiation than blank In2S3.The reason can be mainly acribed to the integrative effect of the boosted separation and transfer efficiency of photogenerated electron-hole pairs and the larger surface area of In2S3-RGO.2.Ternary In2S3-RGO-Pd composites featuring good interfacial contact show further enhanced photoactivity toward selective oxidation of a range of alcohols upon visible light irradiation as compared to the binary In2S3-RGO composites,which results from the introduction of metalic Pd nanoparticles into the interfacial matrix between RGO and In2S3.In this way,the interfacial composition between RGO and In2S3 can be modified,leading to the optimization of the charge carrier transfer pathway across the interface between RGO and the semiconductor In2S3.Additionally,Pd nanoparticles and RGO can act as dual co-catalysts to promote the separation and transfer efficency of photo-induced charge carriers.As a result,the photoactivity of the ternary In2S3-RGO-Pd composites is further boosted.