摘要/Abstract

针对光催化过程中的低光利用率和低催化效率，采用光化学还原法将Ag纳米颗粒均匀修饰在BaTiO₃纳米压电材料表面，制备了x mol/L-Ag/BaTiO₃（x=0.01、0.02、0.04，x为Ag的浓度）等离激元压电光催化剂.研究了压电光催化过程中的反应机理及等离激元颗粒负载的浓度对光催化剂性能的影响.研究结果显示，0.02 mol/L-Ag/BaTiO₃在全光谱光辐照和超声激发的压电场的辅助下，在75 min内可降解91%的罗丹明B，将降解效率提升了21%，证实了纳米复合结构中压电势对表面等离激元光催化活性的重要影响.催化性能的提升源于压电效应和表面等离子体共振效应的协同作用.Ag纳米颗粒的等离子体共振效应（LSPR），使光吸收范围从紫外光区扩大至可见光波段.超声驱动可使BaTiO₃纳米压电体发生形变而于表面产生压电电荷，压电势的存在进一步增强了LSPR诱导的光生载流子分离，促进羟基自由基的生成，加速有机染料的降解.本工作将BaTiO₃的压电效应引入等离子体光催化中，可推广到其他材料和催化系统中，为环境净化提供一种有效的技术.
关键词: 压电电子学, 等离子激元光催化, 纳米压电材料, 局域表面等离子体共振
x mol/L-Ag/BaTiO₃ (x=0.01, 0.02, 0.04, where x is concentration of Ag) plasmonic photocatalysts were fabricated by precipitating Au nanoparticles on BaTiO₃ nano-piezoelectric through a photochemical reducing approach. The plasmonic piezo-photocatalytic composite material can simultaneously solve the problems of low photocatalytic efficiency and narrow light absorption range in the photocatalysis process. BaTiO₃ nano-piezoelectric were synthesized by a hydrothermal synthesis, Ag nanoparticles were deposited on the surface of BaTiO₃ powder using a photoreduction reaction. Subsequently, the effects of microtopography, optical properties and degradation of dye were discussed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray photoelectron spectroscopy (XPS), UV-visible absorption spectra, photocurrent, photoelectrocatalytic, etc. The mechanism of piezoelectric photocatalysis and the effect of the concentration of ionic particles on the properties of the composite photocatalyst were investigated. The intensity and excitation mode of localized surface plasmon resonance (LSPR) vary on account of the different densities of nanoparticles, the 0.02 mol/L Ag-BaTiO₃ showed an excellent photocatalytic performance for degrading 91% RhB in 75 min under full-spectrum light irradiation with ultrasonic excitation which can produce piezoelectric charges on the surfaces of the BaTiO₃ nanocubes, and the degradation efficiency is increased by 21%. The effects of hybrid structure piezoelectric potential in nano-piezoelectric has been confirmed to express a great influence on surface plasmon resonance photocatalytic activity. The improvement of catalytic performance is due to the synergistic effect of piezoelectric effect and surface plasmon resonance effect. The LSPR of Ag nanoparticles that uniformly decorated on the surface of BaTiO₃ nano-piezoelectric, widen the range of light absorption from ultraviolet to visible light. With introducing ultrasonic excitation to renew the piezoelectric charges on the surfaces of the BaTiO₃ nanocubes, the piezoelectric field originated from the deformation of BaTiO₃ nanotubes can further enhance the separation of photo-carriers induced by the localized surface plasmon resonance (LSPR), and promote the generation of hydroxyl radicals with strong oxidizing ability and accelerate the degradation of organic dyes. This work based on the piezotronic effect of the BaTiO₃ nanocubes, assisting the surface plasmon resonance in photocatalysis improved the degradation efficiency of Rh B significantly. In addition, this discovery could be extended to other material systems to provide an effective technology for environment purification.
Key words: piezotronics, plasmonic photocatalysis, nano-piezoelectric, localized surface plasmon resonance


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