High-throughput Screening Of Multi-metal Sulfide Composite GC₃N₄ Photocatalytic Degradation Of Organic Pollutants

In recent years,with the rapid development of human society,a large number of valuable resources on the earth have been consumed,followed by serious environmental pollution problems,and researchers have to work hard to find methods that can solve these problems.At present,photocatalytic degradation is considered as the most environmentally-friendly method to dispose organic pollutants.This technology is to use natural light to stimulate internal photogenic carriers of photocatalysts and generate corresponding high oxidation active groups on the surface of photocatalysts,so as to achieve the purpose of green degradation of organic pollutants.However,this kind of technique cannot be widely used because of its poor stability and difficulty to realize.Therefore,improving the stability and practicability of photocatalysts is the most important issue in this field.However,the traditional catalyst material preparation process is based on the original theoretical basis to repeatedly develop one or several materials,time-consuming and laborious.If the efficiency of preparing and screening catalyst materials can be increased to hundreds of thousands,the speed of research and development of new materials can be effectively increased.High throughput screening technology has the characteristics of fast,micro and sensitive,and it can obtain a lot of information through a single experiment.This technique can establish a catalyst library containing a large number of catalyst materials in a short time,and the catalysts in the library can be screened out and detected to select the appropriate catalyst materials.Graphite carbon nitride(g-C3N4)is a kind of organic polymer semiconductor materials which can response to visible light,and this material sources preparation is simple,strong stability,which has attracted the attention and favor of researchers.For the quantum efficiency of pure g-C3N4 is low,photocatalytic performance is restricted with that.Compounding it with semiconductor materials such as the metal sulfides can effectively reduce the pure g-C3N4 carrier recombination rate,so as to improve the photocatalytic performance.Our research established a photocatalyst library consisted of hundreds of various metal sulfide and g-C3N4 using high-throughput screening technology,and examined the catalytic properties of photocatalytic materials.At last we have screened out the high catalytic activity photocatalysts.The main content of the experiment is as follows:(1)Preparation of reaction chips:the hydrophobic polytetrafluoroethylene dispersion solution was printed on the glass slides by glass printing technology,and 225 independent reaction grids were formed on the slides providing a space for preparation and reaction of the catalyst(2)Preparation of photocatalysts:we selected four kinds of metal sulfide as and gC3N4 compound semiconductors,and among these four kinds of metal(Zn?Cu?Ni and Cd),we selected three to prepare multiple metal sulfides compounding with g-C3N4,After that,g-C3N4 was evenly dispersed in the reaction chips using ultrasonic atomizer,then using inkjet printing technology to print these metal solutions into g-C3N4.At last,the metal sulfides was synthesized by sulfuration.(3)The establishment of testing methods:according to the concentration of the organic fluorescent dyes is proportional to the fluorescence intensity,in the process of photocatalytic degradation of organic dyes,organic dye fluorescence intensity and its solution concentration will fade out with the ongoing of the degradation process.The fluorescence images of organic dyes were recorded by the camera to.(4)The screening of highly active catalyst:there were four reaction chips made in this experiment,each reaction chip was made by the same methods:the organic dye was evenly sprayed on reaction chip,and then we put it in the detection device with 365 nm ultraviolet light to illuminate.Then we use the camera to record the fluorescence intensity changes in the process of photocatalytic reaction at different times,and screen out the highly active catalyst using the image processing software filter fluorescence intensity changes during the process of photocatalytic reaction.Finally,the following four highly active catalysts were selected from the four reaction chips:ZnxCdyNi2S/g-C3N4?ZnxCdyCuzS/g-C3N4?ZnxCuyNizS/g-C3N4 and CdxCuyNizS/g-C3N4(x+y+z=1).(5)Contrast experiments:by comparison and validation tests,screening process can be determined through the experiment of catalyst has higher photocatalytic activity.Through the above experimental research,it can provide a practical research method for rapid preparation and screening of catalysts with high catalytic activity,which will greatly reduce the development time and preparation cost of traditional photocatalytic materials.