Preparation And Photocatalytic Activity Of Piezotronic Effect Enhanced Plasmonic Photocatalysis By （Au,Ag,Ag₂S）/BaTiO₃

The piezoelectric effect of nanoscale piezoelectric materials can capture low frequency vibrational energy in the environment.Some bifunctional material systems that couple piezoelectric and semiconductor properties utilize basic research in piezoelectric electronics to enable piezoelectric potential to effectively regulate carrier activity.Photocatalytic technology is a green and safe environmental energy solution,so the use of nano-piezoelectric structures to further improve photocatalytic efficiency has great potential applications.The localized surface plasmonic resonance（LSPR）of dispersed precious metal nanocrystals have rich reaction sites and wide photoresponse range,which provides a new direction for designing and improving piezoelectric photocatalytic materials.Aiming at the low photocatalytic efficiency and low light response in the catalytic process,this paper proposes a new idea:combining the piezoelectric effect and the plasmonic resonance effect to modify the traditional photocatalytic material,synthesizing（Au,Ag,Ag₂S）/BaTiO₃ plasma piezoelectric The photocatalytic material utilizes the coupling of the LSPR effect and the piezoelectric potential to improve the catalytic activity,and provides a simple and low-cost method for preparing a high-performance photocatalyst.Firstly,Au/BaTiO₃ piezoelectric plasmonic photocatalyst was prepared by hydrothermal-deposition precipitation method.The plasma induced photocatalysis was enhanced by ultrasonically induced piezoelectric potential,and high-efficiency piezoelectric photocatalytic activity was realized.The mechanism of photocatalytic reaction.The carriers generated by the Au nanoparticle-induced LSPR effect are key factors in the formation of OH·and oxidative degradation of organic dyes.The built-in electric field formed by piezoelectric polarization can effectively separate and transport the charge carriers generated by Au/BaTiO₃ materials under photoexcitation,which effectively enhances the photocatalytic activity of the materials.The effects of reactant concentration and reaction pH on the microstructure,optical properties and catalytic degradation of the composites were further studied.As the concentration of Au³⁺increases,the optical properties and photocatalytic activity of Au/BaTiO₃ samples increase,while at large concentrations,they show attenuation.The Au4/BaTiO₃ shows the fastest degradation rate in the degradation rate of organic dyes.When the pH of the reaction solution was controlled at 11,the sample had the best optical properties and catalytic activity.Subsequently,in order to reduce the cost and further broaden the light absorption band,a new piezoelectric/plasma photocatalyst of Ag/BaTiO₃ was prepared by hydrothermal-photochemical reduction two-step method,and the high-efficiency piezoelectric photocatalytic activity similar to that of Au was realized.It was confirmed that the synergistic effect of the piezoelectric effect and the surface plasmonic resonance effect together promoted the improvement of the catalytic performance.The effects of reaction time and reactant concentration on Ag/BaTiO3 composite photocatalytic materials were also investigated.As the reaction time increases,the particle size distribution disorder increases.The 1mAg/BaTiO₃ has the best optical properties and photocatalytic degradation under piezoelectric polarization and light irradiation,and achieves 83%degradation rate of Rh B in 75 minutes.When the concentration of Ag is 0.02 mol/L,91%of Rhodamine B can be degraded in 75 min.The effect of plasma particle morphology on plasma photocatalysis was verified.Then,due to the excellent absorption coefficient and chemical stability of Ag2S material,and the novel non-precious metal LSPR characteristics,we further vulcanize Ag-BaTiO3to prepare Ag₂S/BaTiO₃ composite nanoplasma piezoelectric catalyst,due to piezoelectric effect,The synergistic effect of the pn heterostructure and surface plasmonic resonance effects improves the catalytic performance.On the one hand,Ag₂S can induce LSPR as non-metal plasmonic nanoparticles,and on the other hand,it builds a bifunctional cocatalyst of pn heterostructure due to its narrow band gap,which further broadens the optical absorption band and improves the photocatalytic efficiency.It was confirmed that the heterostructure and piezoelectric potential have a great influence on the photocatalytic activity of the plasma in the nano-piezoelectric.The effect of reactant concentration on Ag₂S/BaTiO₃ piezoelectric plasmonic photocatalytic materials was investigated.After vulcanization,the size of Ag₂S nanoparticles increased slightly.As the concentration of the reactants increases,the Ag₂S nanoparticles gradually grow and become irregular.0.02M-Ag2S/BaTiO3 can degrade 99%rhodamine B in 60 min with the help of full-spectrum light irradiation and ultrasonically excited piezoelectric field,which improves the degradation efficiency by 32%and significantly improves Rh B.Degradation efficiency.