Study On Preparation And Performance Of Non-metal Quantum Dots/Red Phosphorus Composite Photocatalyst

As an environmentally friendly green technology,photocatalytic technology has excellent application prospects in areas such as mitigating energy crises and solving environmental problems.As one of the most abundant elements on earth,non-metal photocatalyst red phosphorous has shown great potential in the application of photocatalytic technology due to strong sunlight absorption capacity,low cost and easy access.However,the shortcomings of the easy recombination of photogenerated electrons and holes and low catalytic efficiency severely restricts its application.Therefore,in order to further improve its photocatalytic activity,this subject adopts an effective strategy to modify red phosphorus,which lays a foundation for its practical application in water pollution control.The details are as follows:(1)Using boric acid as the boron source and melamine as the nitrogen source,boron nitride quantum dots are prepared by a simple hydrothermal method.Commercial red phosphorus is also prepared by a hydrothermal method to obtain hydrothermal red phosphorus with smaller particle size and better catalytic activity,and then combine them to prepare boron nitride quantum dots/red phosphorus composite material(BNQDs/RP).And the structure,composition,micromorphology and optical properties of the catalyst are analyzed through XRD,FT-IR,XPS,TEM,BET,UV-vis DRS and photoelectrochemical testing and other characterization methods.The organic dyes malachite green and rhodamine B were degraded to evaluate the photocatalytic activity of the composite under visible light irradiation.The experimental results showed that the degradation effect of BNQDs/RP-3 was the best,and the degradation rate of malachite green can reach 91%within 25 minutes.The reaction rate constant is 2.27 times that of red phosphorus;The degradation rate of rhodamine B can reach 85%within 60 minutes,and the reaction rate constant is 2.24 times that of red phosphorus.The introduction of boron nitride quantum dots can effectively attract holes generated by light excitation in red phosphorus and accelerate their transfer,thereby improving the separation of photogenerated electrons and holes,and enhancing the photocatalytic performance.(2)Using anhydrous citric acid as the carbon source and ethylenediamine as the nitrogen source,the nitrogen-doped carbon quantum dots were prepared hydrothermally,and then compounded with hydrothermal red phosphorus to obtain nitrogen-doped carbon quantum/red phosphorus composite photocatalyst(NCQDs/RP).The catalysts have been explored the structure,composition,microscopic morphology and optical properties of the catalyst through XRD,FT-IR,XPS,TEM,UV-vis DRS and photoelectrochemical testing.The experimental results show that the organic dye Rhodamine B is used as target pollutant.The composite photocatalyst 20%N-CQDs/RP has the best degradation performance.The degradation rate of Rhodamine B can reach 95%within 40 minutes,and the reaction rate is 3.5 times that of red phosphorus.N-CQDs,as an electron acceptor,can effectively promote the migration of photogenerated electrons in red phosphorus and facilitate the separation of photogenerated electron-hole pairs.At the same time,N-CQDs can broaden the visible light absorption range of RP and promote its visible light responsiveness.Therefore,the photocatalytic performance of red phosphorus is significantly improved.