Preparation And Performance Study Of Zn-Ti LDH-based Composite Visible Light Photocatalyst

With the rapid development of industrialization,various organic pollutants have entered the environment,causing various environmental problems and possibly harming human health.Therefore,how to control organic pollutants is an important issue.Photocatalysis technology is often used for the degradation of organic pollutants,and its technical core is the photocatalyst.Semiconductor photocatalysts have been widely used in photocatalysis technology,and different material systems have been developed.Among the materials studied,ion-exchangeable materials have attracted much attention due to their unique structures and photocatalytic properties.As one of the ion exchange materials,layered double hydroxide photocatalysts with photosensitive elements can effectively degrade organic pollutants.Therefore,Zn-Ti LDH is prepared in this paper.Although Zn-Ti LDH is easy to prepare and its structure is durable and sustainable,the mobility of photogenerated carriers in Zn-Ti LDH is not high enough,and the solar energy conversion efficiency is relatively low.In this paper,we further study the heterojunction formed between Zn-Ti LDH and g-C₃N₄to improve the separation efficiency of photogenerated electrons and the utilization rate of solar energy.Therefore,in this paper,the heterojunction formed between Zn-Ti LDH and g-C₃N₄is further studied to improve the separation efficiency of photo-generated electrons and solar energy utilization.And also loaded Ag nanoparticles on its surface can form plasmon resonance,which promotes the movement of electrons and further improves their photocatalytic performance.Through photocatalytic degradation of different pollutants and hydrogen production under visible light,the possible photocatalytic mechanism is explored.The paper focuses on the following:?1?Using zinc nitrate and titanium tetrachloride as the zinc source and titanium source,and then adding urea,hydrothermal method is successfully used to synthesize Zn-Ti LDH nanosheets with layered structure with different Zn²⁺and Ti⁴⁺ratios.The degradation of bisphenol A,dichlorophenol and trichlorophenol shows that Zn-Ti LDH has a response in the visible light region,has photocatalytic performance and stable performance,and can also hydrolyze to produce hydrogen.A possible photocatalytic reaction mechanism is proposed based on characterization and performance tests.Zn-Ti LDH has the ability of light absorption,which is caused by the interlayer space promoting the charge recombination of photo-generated charge carriers and the inhibiting reactants.Moreover,interlayer water and hydronium ions in the interlayer space of Zn-Ti LDH enhance photocatalytic activity through effective charge separation.?2?Using melamine as a precursor,a sheet of g-C₃N₄is successfully prepared,and then a layered Zn-Ti LDH/g-C₃N₄heterojunction composite is synthesized by a one-step in-situ hydrothermal method.The degradation of bisphenol A,dichlorophenol and trichlorophenol can reach 92%.In the photocatalytic hydrogen production experiment,the hydrogen production rate is 161.87?mol·h^-1·g^-1,and it is proposed based on the characterization and performance tests.Possible photocatalytic reaction mechanism.Zn-Ti LDH/g-C₃N₄has strong light absorption ability,which is due to the existence of a strong van der Waals heterojunction between g-C₃N₄and Zn-Ti LDH.The improvement of light absorption in the visible light region can generate more photocatalytic charge carriers for subsequent photocatalytic reactions,thereby improving photocatalytic performance.?3?Using melamine as a precursor,a sheet of g-C₃N₄is successfully prepared,and then a layered Zn-Ti LDH/g-C₃N₄heterojunction composite is synthesized by a one-step in-situ hydrothermal method,and then photo-deposited The method was to prepare Ag/Zn-Ti LDH/g-C₃N₄.The degradation of bisphenol A,dichlorophenol and trichlorophenol can reach 99%.In the photocatalytic hydrogen production experiment,the hydrogen production rate is 186.78?mol·h^-1·g^-1,and it is proposed based on the characterization and performance tests.Possible photocatalytic reaction mechanism.Ag/Zn-Ti LDH/g-C₃N₄has strong light absorption ability,which is caused by the existence of strong van der Waals heterojunction between g-C₃N₄and Zn-Ti LDH and the surface plasmon resonance of Ag.The improvement of light absorption in the visible light region can generate more photocatalytic charge carriers for subsequent photocatalytic reactions,thereby improving photocatalytic performance.