Preparation,Modification And Performance Study Of Ultra-thin 2D In₂S₃/g-C₃N₄ Composite Photocatalyst

Photocatalysis technology Photocatalysis technology has broad application prospects in solving environmental pollution problems and developing new energy sources.First,the photocatalytic material itself does not cause pollution to the environment and can be recycled many times;secondly,the photocatalytic process only needs to be driven by sunlight,which can be widely used;and finally,on environmental issues,photocatalytic materials It can completely degrade pollutants into environmentally friendly H₂O and CO₂.In addition,in terms of energy,it can decompose water into H₂ and O₂,and can also reduce carbon dioxide into carbon monoxide,methane and other sustainable green energy sources.The ultra-thin 2D material has a thickness of only a few atoms,and exhibits excellent optical,electrical and other physical and chemical properties,making it of great value in the field of photocatalysis.First,the ultra-thin 2D material has the characteristic of single or several atoms thickness,which can greatly shorten the migration distance of electrons.At this time,the carriers generated in the ultra-thin two-dimensional photocatalytic material can quickly migrate to the surface,making the photogenerated The recombination probability of carriers is greatly reduced,which has a positive effect on the progress of photocatalytic reactions.Second,ultra-thin 2D materials have a larger specific surface area and more low-coordinate surface atoms,which can absorb more sunlight,while the photon absorption in bulk materials is usually affected by the light transmittance at the grain boundaries and Limitations of reflection.Finally,ultra-thin 2D materials have a high proportion of surface atoms.The more active sites that play a key role in the photocatalytic reaction process,the more favorable the catalytic reaction will be.In addition,when the thickness of the material is reduced to the atomic level,a large number of defects may be generated on the surface.The presence of surface defects can better adsorb the target molecules and help the photocatalytic reaction.The existence of these unique properties makes ultra-thin two-dimensional materials show great research value in the field of photocatalysis.Graphite-like carbon nitride?g-C₃N₄?is a non-metallic photocatalytic material with high photocatalytic activity under visible light conditions,which is comparable to most metal-containing photocatalytic materials.It has a bandgap width of approximately 2.7eV,high stability,in addition,its preparation process is simple,the price is relatively low,and no pollution to the environment,while g-C₃N₄ can achieve a variety of photocatalytic applications,such as hydrogen release,CO₂ reduction,pollutant removal,etc..However,the inability of photo-generated carriers to be effectively separated makes its photocatalytic activity relatively low,which limits its practical application.It requires effective methods to improve the separation of photo-generated electrons and holes.The key to the photocatalytic activity of g-C₃N₄.We use a simple low-temperature reflow device to combine ultra-thin 2D In₂S₃ nanosheets with ultra-thin 2D g-C₃N₄ nanosheets,and use a series of characterization methods such as XRD,SEM/TEM,FTIR,XPS,DRS,etc.to prepare The ultra-thin 2D In₂S₃/g-C₃N₄composite sample was characterized,which confirmed that the ultra-thin 2D In₂S₃nanosheet was successfully combined with the ultra-thin 2D g-C₃N₄ nanosheet.Through PL and electrochemical tests,the ultra-thin The combination of 2D In₂S₃nanosheets and ultra-thin 2D g-C₃N₄ nanosheets can effectively promote the separation of photogenerated electrons and holes.The 50%In₂S₃/g-C₃N₄ composite sample has the best separation effect between photogenerated electrons and holes.At the same time,through DRS testing,it was found that 50%In₂S₃/g-C₃N₄ composite samples absorb light wider than pure ultra-thin 2D In₂S₃ nanosheets and ultra-thin 2D g-C₃N₄nanosheets.When the visible light was irradiated for 60 min,the photocatalytic degradation rate of tetracycline hydrochloride of 50%In₂S₃/g-C₃N₄ composite sample reached 83.54%,indicating that the 50%In₂S₃/g-C₃N₄ composite photocatalyst had excellent photocatalytic performance.The rational design of the heterojunction is the most effective measure to promote the separation of photogenerated carriers.Among the various heterojunction construction schemes,the advantage of the Z-scheme heterojunction is that it retains a strong reduction of a photocatalyst The electrons and strong oxidized holes participate in the photocatalytic reaction process,so that the entire photocatalyst exhibits stronger reducing ability and oxidizing ability.Using graphene as an electron mediator to construct a Z-scheme heterojunction can not only effectively promote the transfer of photogenerated electrons,but also greatly increase the absorption of light.We prepared the ultra-thin 2D Z-scheme heterojunction g-C₃N₄/RGO/In₂S₃ composite photocatalyst through a two-step simple low-temperature reflow device,and performed a series of characterizations on the composite samples,such as XRD,SEM/TEM,The characterization of XPS confirmed the successful combination of g-C₃N₄,RGO,and In₂S₃.Through DRS testing,it can be seen that the g-C₃N₄/RGO/In₂S₃ composite photocatalyst has a light response in the entire visible range.The light absorption of 50%In₂S₃/g-C₃N₄ composite photocatalyst is stronger and wider.Through PL and electrochemical tests,the g-C₃N₄/RGO/In₂S₃ composite photocatalyst is more prominent than the 50%In₂S₃/g-C₃N₄ composite photocatalyst in separating photogenerated electrons and holes.Through the test of the degradation performance of tetracycline hydrochloride,it was found that the degradation rate of tetracycline hydrochloride reached 86.26%when the g-C₃N₄/RGO/In₂S₃ composite photocatalyst was exposed to visible light for 60 min,and the complete degradation of tetracycline hydrochloride was basically achieved.It shows that when RGO is used as an electron mediator,it can effectively improve the photocatalytic performance of samples.