Fabrication And Photocatalytic Performance Of Ag₂O-based Catalyst

Today,as the process of urbanization and industrialization continues to advance,the natural environment on which people depend for survival has been severely damaged.The accumulation rate of organic matter in natural waters has exceeded the maximum load of water bodies,completely surpassing the self-purification capacity of water bodies.The impact of watre pollution directly threatens us.At present,the countermeasures applied to the current environmental pollution in the world mainly include physical methods,chemical methods,biological methods and biochemical methods.However,these traditional methods for governing water bodies have disadvantages such as insufficient degradation,large floor space,high operating cost,complicated operation,and high energy consumption.In order to solve these problems,we use the ability of semiconductor materials can respond sunlight and applying semiconductor photocatalytic materials to wastewater treatment because of its high photocatalytic degradation efficiency stable chemical properties,and large reserves of raw materials.And photocatalytic water treatment technology has become a research hotspot.Ag₂O has a band gap of 1.3eV,which is a nanomaterial with narrow band gap.It has the advantages of active chemical properties,and large response range to visible light.It is a nanoparticle photocatalytic material with great development potential.In order to optimize the performance of Ag₂O,we will use it as a substrate and use other semiconductor materials and Ag₂O to form a heterostructure photocatalyst,and also encapsulate Ag₂O on the surface of the magnetic material to solve the problem of difficult recycling.We successfully prepared?-FeOOH/Ag₂O and Ag-Ag₂O@Fe₃O₄nanoparticle photocatalysts by mild hydrothermal and chemical precipitation methods,which reduced the recombination of photogenerated electron hole pairs and accelerated the separation energy of photogenerated electron hole pairs to some extent.Crystal form,morphology,structure and optical properties of Ag₂O-based nanoparticle photocatalysts by X-ray diffraction?XRD?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,UV-visible diffuse reflectance spectroscopy?DRS?and optoelectronics Chemical analysis characterization.The following research results were obtained through specific experiments:?1?Using hydrothermal method,nine water and ferric nitrate as iron sources and sodium hydroxide as a precipitant,a short rod-shaped?-FeOOH nanocatalyst was prepared by controlling the pH of the reaction;and The Ag₂O nanoparticle photocatalyst was successfully prepared by mild chemical precipitation method using silver nitrate as raw material and sodium hydroxide as precipitant.?-FeOOH/Ag₂O heterostructure photocatalyst was prepared by wet chemical method.The composite nanoparticle photocatalyst was characterized by many characterization methods.The results showed that we successfully constructed a well-formed nanoparticle-like heterostructure?-FeOOH/Ag₂O catalyst.Compared with pure Ag₂O nanoparticle photocatalyst,?-FeOOH/Ag₂O nanoparticles have a higher photodegradation efficiency of photocatalytic degradation of rhodamine B aqueous solution under visible light irradiation.The reason may be that the photocatalyst of the heterostructure has a stronger absorption ability for visible light and a lower separation rate of photogenerated electron-hole pairs.?2?The superparamagnetic Fe₃O₄ magnetic powder was prepared by coprecipitation method using?NH₄?₂Fe?SO₄?₂·6H₂O and?NH₄?Fe?SO₄?₂·12H₂O as iron sources and sodium hydroxide as coprecipitation agent.The Ag-Ag₂O@Fe₃O₄ nanoparticle photocatalyst is prepared in two steps by a mild chemical precipitation method and a photoreduction method.In the preparation of Ag₂O@Fe₃O₄,we added the emulsifier polyethylene glycol?PEG-4000?to improve its properties.The results of XRD indicate that the crystal form of Ag₂O has a certain change,and the X-ray diffraction intensity is higher and the peaks are less.Then we further supported the photocatalytic activity by loading Ag on the prepared Ag₂O@Fe₃O₄ magnetic material by photoreduction.The photocatalytic activity test was carried out by photocatalytic degradation of rhodamine B aqueous solution under visible light.It can be found that the nanoparticle photocatalyst loaded with Ag after adding emulsifier has better photocatalytic effect,indicating that the composite system is optimized after adding emulsifier.It can enhance photocatalytic activity.