Preparation And Photocatalystic Activity Of P And S Elements Doped G-C₃N₄ Photocatalyst

With the development of industrial technology,environmental pollution and energy shortage are becoming seriously.Since the advent of photocatalysis,it has attracted much attention because it can convert solar energy into chemical energy.In photocatalytic technology,the core of its development is the development of photocatalyst materials.In recent years,the rapid development of photocatalyst materials has provided great support for the application of photocatalysis technology in the field of energy.Graphite carbon nitride?g-C₃N₄?is a semiconductor polymer photocatalyst material.It has a series of advantages such as suitable band structure?Eg=2.7 eV?,visible light response ability,good thermal stability,simple preparation method and low cost,etc.,and is widely used in the field of photocatalysis.However,g-C₃N₄ also has a series of inherent defects that still restrict its development in the field of photocatalysis,such as small specific surface area,photogenerated electron-hole readily recombined and weak visible light response ability.Based on the above analysis,the photocatalytic activity of g-C₃N₄ photocatalyst was improved by simple doping of different impurity atoms,such as increasing its specific surface area,inhibiting its photogenerated electron-hole recombination and enhancing its visible light response.Specific research results include the following two aspects:?1?In this part experiment,the photocatalysts with hollow porous worm-like structure was successfully achieved from urea and sodium dihydrogen phosphate.According to a series of characterization methods,the lamellar structure of the photocatalyst after modification has a pore structure with an aperture of about 50 nm and an increased specific surface area.At the same time,the structure provide more active sites for photocatalytic reaction,and improves the optical photogeneration electronic-hole separation efficiency.The results of photocatalytic hydrogen production test show that when the content of dihydrogen phosphate is 15%,the hydrogen production of the photocatalyst is up to 10.985 mmol/g,which is about 7.6 times of the pure g-C₃N₄.?2?In this part of the experiment,the sulfur-doped ultra-thin nanosheet porous g-C₃N₄photocatalyst was successfully synthesized by using urea as the precursor and amidinothiourea as the sulfur source.This photocatalyst has a high visible light absorption capacity and a high photogenerated electron-hole separation efficiency,due to its special structure,it has a large specific surface area,which provides more active sites for photocatalytic reaction,and can promote the photocatalytic reaction.In addition,the photocatalytic hydrogen production activity and stability of the photocatalyst were tested.The results showed that when the amidinothiourea content was 5 mg,the photocatalytic activity of the photocatalyst was the highest,and the hydrogen production was 9.54 mmol/g,which was 6.6 times of the pristine g-C₃N₄.At the same time,the photocatalytic hydrogen production of the modified photocatalyst did not decrease significantly in 4 times of photocatalytic cycle experiments,which indicated that the photocatalytic stability of the modified catalyst was excellent.