【作者】 李磊；

【导师】 方应翠；

【作者基本信息】 合肥工业大学 ， 流体机械及工程， 2022， 硕士

【摘要】 银纳米颗粒的局域表面等离激元共振(LSPR)吸收波长位于可见光范围,能利用可见光诱导催化反应,因此在光催化方面应用广泛。但是银纳米颗粒LSPR产生的热电子-空穴对容易复合,导致其光催化性能下降,文献报道银纳米颗粒和铜纳米颗粒复合形成的铜银双金属纳米颗粒,由于协同效应的作用,其催化和光催化性能得到显著改善。为探究其催化机理,本文先分别研究了铜、银纳米颗粒的光催化性能和催化机理,在此基础上进一步研究了层状和核壳构型铜银复合双金属纳米颗粒的催化和光催化性能,并通过捕获剂实验和样品表征探索其催化机理。围绕以上主题,本文开展了以下工作:第一部分采用真空蒸发镀工艺分别制备了铜、银纳米颗粒,然后采用表面增强拉曼散射光谱实时监测了铜、银纳米颗粒对对硝基苯硫酚(PATP)和对氨基苯硫酚(PNTP)分子的选择性光催化效率。结合样品表征,发现在光催化氧化PATP方面,铜、银纳米颗粒表现出相似的光催化性能,光催化效率随样品LSPR效应的增强而增大。在光催化还原PNTP方面,铜、银纳米颗粒表现出不同的LSPR光催化还原性能;而退火后的铜纳米颗粒表现出和银纳米颗粒相似的光催化还原性能。第二部分采用真空蒸发镀工艺分别制备了Cu-Ag层状和Cu@Ag核壳状两种复合构型,研究了两种铜银复合构型的催化和光催化性能。研究表明,在选择性光催化转化PNTP时,Cu-Ag层状构型的光催化活性大于铜、银之和;在降解R6G染料时,Cu-Ag层状构型在光照条件下表现出较强的光催化活性,而Cu@Ag核壳构型在无光条件下表现出较大的暗催化活性。结合对两种铜银复合构型的表征,通过电子、空穴捕获剂实验和对铜银接触电位的分析,探索了两种铜银复合构型的催化和光催化机理。研究发现,两种铜银复合构型均可高效分离催化剂内部的电子-空穴对,而外延生长的Cu-Ag层状构型还具备高效输运热载流子的特性。因此,Cu-Ag层状构型具有显著放大的光催化性能。本研究阐明了铜银复合双金属纳米颗粒的催化机理,有利于铜银复合双金属纳米颗粒催化剂在催化领域的合理应用。更多还原

【Abstract】 The localized surface plasmon resonance(LSPR)absorption wavelength of silver nanoparticles(Ag NPs)is located in the visible light range,and can utilize visible light to induce catalytic reactions,so it is widely used in photocatalysis.However,the hot electron-hole pairs generated by the LSPR of Ag NPs are easy to recombine,which leads to the decline of its photocatalytic performance.It has been reported in literature that the copper-silver bimetallic nanoparticles formed by the composite of Ag NPs and Cu NPs,due to the synergistic effect,their catalytic performance is reduced.and photocatalytic performance was significantly improved.In order to explore its catalytic mechanism,the photocatalytic performance and catalytic mechanism of copper and silver nanoparticles were firstly studied in this paper.On this basis,the catalytic and photocatalytic performance of layered and core-shell configuration copper-silver composite bimetallic nanoparticles were further studied and explore its catalytic mechanism through capture agent experiments and sample characterization.Around the above themes,this paper has carried out the following work:In the first part,copper and silver nanoparticles were prepared by vacuum evaporation plating process,and then surface-enhanced Raman scattering spectroscopy was used to monitor the Cu NPs and Ag NPs p-nitrothiophenol(PATP)and p-aminothiophenol(PNTP)molecular selective photocatalytic efficiency in real time.Combined with sample characterization,it was found that Cu NPs and Ag NPs exhibited similar photocatalytic performance in terms of photocatalytic oxidation of PATP,and the photocatalytic efficiency increased with the enhancement of the LSPR effect of the sample.In terms of photocatalytic reduction of PNTP,Cu NPs and Ag NPs showed different LSPR photocatalytic reduction efficiencies;while the annealed Cu NPs showed similar photocatalytic reduction performance as Ag NPs.In the second part,two composite configurations of Cu-Ag layered and Cu@Ag coreshell were prepared by vacuum evaporation plating process,and the catalytic and photocatalytic properties of the two Cu-Ag composite configurations were studied.Studies have shown that the Cu-Ag layered configuration exhibits significantly amplified photocatalytic activity in the photocatalytic degradation of rhodamine 6G(R6G)and the selective photocatalytic conversion of PNTP;while the Cu@Ag core-shell configuration is only in the absence of When photodegrading R6 G dyes,it showed high catalytic efficiency.Combined with the characterization of the two Cu-Ag composite configurations,the catalytic and photocatalytic mechanisms of the two Cu-Ag composite configurations were explored through electron and hole trapping experiments and the analysis of Cu-Ag contact potential.The study found that both Cu-Ag composite configurations can efficiently separate electron-hole pairs inside the catalyst,while the epitaxially grown Cu-Ag layered configuration also has the characteristics of efficient transport of hot carriers.Therefore,the Cu-Ag layered configuration has significantly amplified photocatalytic performance.This study clarifies the catalytic mechanism of copper-silver composite bimetallic nanoparticles,which is beneficial to the rational application of copper-silver composite bimetallic nanoparticles in the field of catalysis.更多还原