Determination of the flat band potential of doped and non-doped nanoparticles in aqueous environment using a novel electrode preparation method

对于许多应用，特别是对于毒性的评估，纳米颗粒的电化学性质是必不可少的。这些与纳米颗粒的平带电势（即电化学电势）有关，其取决于合成方法并且可以通过将外来原子掺杂到纳米颗粒中来改变。电化学电势也对ζ电势有影响，ζ电势决定悬浮液中颗粒的聚集行为和在水性生物环境中进行的表面反应。精确的平带势的纳米粒子的知识将大大提高我们对粒子表面电荷的理解。然而，电化学表征的纳米粒子通过阻抗谱使用多孔电极，这保持了纳米粒子的表面特性，是有限的，由于干扰的贡献的基板-电解质接触。我们建议的目的是开发和从根本上理解一种新的电极制备方法，该方法允许阻止多孔电极的基底-电解质接触的干扰贡献，并能够在水性环境中快速表征颗粒。随着我们的电极制备方法的成功实施，我们能够确定纳米颗粒的平带电位，并评估掺杂允许改变纳米颗粒的电化学性质（即平带电位和zeta电位）的程度。

For many applications and especially for an evaluation of the toxicity, the electrochemical properties of nanoparticles are essential. These are related to the flat band potential, i.e. the electrochemical potential, of the nanoparticles, which depends on the synthesis method and may be modified through doping of foreign atoms into the nanoparticles. The electrochemical potential also has an influence on the zeta-potential that determines the agglomeration behavior of particles in suspensions and the surface reactions proceeding in aqueous biological environments. The knowledge of the exact flat band potential of nanoparticles would greatly enhance our understanding of particle surface charges. However, the electrochemical characterization of nanoparticles via impedance spectroscopy using porous electrodes, which preserve the nanoparticles surface properties, is limited due to the disturbing contributions of the substrate-electrolyte contact. The aim of our proposal is to develop and fundamentally understand a novel electrode preparation method, which allows to block the disturbing contribution of the substrate-electrolyte contact of the porous electrodes and enables a fast particle characterization in aqueous environments. With the sucessful implementation of our electrode preparation method we are able to determine the flat band potential of nanoparticles and assess to which extend doping allows for a modification of the electrochemical properties, i.e. the flat band potential and the zeta-potential, of the nanoparticles.