Preparation And Photocatalytic Dye Degradation Of Cuprous Oxide And Its Compounds

In recent years,the rapid development of China's industrialization has caused more and more damage to the environment,and our health,life,learning and ecological balance have been greatly threatened.Dye wastewater has caused damage to the water environment,environmental pollution and social problems are becoming more and more prominent,but traditional water treatment methods are difficult to deal with organic substances such as dyes that are difficult to degrade in the water body,so the problem of dye wastewater pollution cannot be ignored and needs to be resolved urgently.The use of green photocatalytic technology to treat dye wastewater has the advantages of cleanness,no secondary pollution,and no toxicity.Therefore,the development of photocatalytic technology for efficient degradation of dye wastewater is of great significance.The cuprous oxide band gap is about 2.17 e V,andcan be excited to generate hole-electron pairs in the visible light range.Therefore it has good responsiveness to visible light,however still has the disadvantages of insufficient photocatalytic activity and prone to photocorrosion.This obviously limits its practical application in environment pollution.Due to the severe pollution control.In view of the increasingly serious pollution of water environment and the shortcomings of cuprous oxide photocatalyst,this paper uses benzoic acid as a structural regulator,using low temperature liquid precipitation method to prepare cuprous oxide photocatalyst and Cu₂O/rGO photocatalyst respectively.A variety of characterization methods such as FESEM,FTIR and XRD were used to observe the structure and morphology of the Cu₂O photocatalyst and Cu₂O/rGO photocatalyst.The effects of preparation conditions and photocatalytic conditions on the performance of photocatalytic degradation of dyes for Cu₂O photocatalyst and Cu₂O/rGO photocatalyst were studied.The recycling performance of the Cu₂O photocatalyst and Cu₂O/rGO photocatalyst were investigated.Photocatalytic dye degradation mechanisms of Cu₂O photocatalyst and Cu₂O/rGO photocatalyst were also studied.The main work is as follows:1.In the synthesis condition of the reduction temperature of 30oC,the reaction p H of 6,the reduction reaction time of 1.5h,the molar ratio of copper ion/VC of 1:0.7 and the molar ratio of copper ion/organic acid of 1:2.5,the photocatalytic degradation performance of the cuprous oxide photocatalyst reached the maxmium,respectively,and the photocatalytic degradation performance of the cuprous oxide photocatalyst reached 97.5%after the LED lamp illumination for 60 minutes.In the synthesis condition of the amount of graphene oxide of 1.5%,the reaction p H of 6,and the molar ratio of copper ion/ascorbic acid of 1:2,the photocatalytic degradation performance of Cu₂O/rGO photocatalyst for photocatalytic degradation of dyes reached the maxmium,respectively.The photodegradation of methyl orange dye by Cu₂O/rGO photocatalyst can reach 98.5%after the LED lamp illumination for 50minutes.2.When the initial concentration of methyl orange dye is 10 mg/L and 30mg/L,the photodegradation of methyl orange dye for Cu₂O photocatalyst and Cu₂O/rGO photocatalyst is 97.4%,82.7%and 60.98.2%and 84.5%,respectively.When the amount of photocatalyst was 0.01g and 0.04g,photodegradation of methyl orange dye by Cu₂O photocatalyst after 60 minutes light exposure and Cu₂O/rGO photocatalyst after 50 minutes light exposure was 67.6%,97.3%,71.9%and 98.5%,respectively.After five cycles of recycling,the photodegradation of methyl orange dye by Cu₂O and Cu₂O/rGO photocatalysts can still reach 85.1%and 86.2%,respectively.3.XRD shows that the characteristic diffraction peaks of cuprous oxide appear on the cuprous oxide photocatalyst and Cu₂O/rGO photocatalyst,and the characteristic diffraction peaks of copper oxide and zero-valent copper do not appear.FTIR,XRD and Raman spectroscopy showed that the graphene oxide prepared by Hummers improved method had the target structure.FTIR preliminary showed that Cu₂O photocatalyst and Cu₂O/rGO photocatalyst had the target structure.The cuprous oxide photocatalyst and the Cu₂O/rGO photocatalyst have good responsiveness to visible light,with energy gaps of 2.10 e V and 2.05 e V,and corresponding absorption edges of 590.5 nm and 605 nm,respectively.4.We can observe that the shape of the cuprous oxide photocatalyst is spherical nanoparticles with a particle size of 30-50 nm and a narrow particle size distribution by way of FESEM.The Cu₂O/rGO photocatalyst has a porous structure with an average particle size of 40-60 nm.Cuprous oxide particles are attached to the surface of reduced graphene with a layered structure.The cuprous oxide photocatalyst has an atomic ratio of copper atoms and oxygen atoms of 2.07:1.The Cu₂O/rGO photocatalyst has carbon atoms,oxygen atoms,and copper atoms with the atomic ratio of copper/oxygen of 1.375:1.5.The hole?h⁺?,superoxide ion free radical?O₂^-·?and hydroxyl free radical?OH·?are the photocatalytic active species for the photocatalytic degradation of dyes by cuprous oxide photocatalyst and Cu₂/rGO photocatalyst.The contribution sequence of different active species during the photocatalytic dye degradation process of cuprous oxide photocatalyst and Cu₂O/rGO photocatalyst is h+,O₂^-·,and OH·.