Laurinavichyute Veronika K, Nizamov Shavkat, Mirsky Vladimir M
Nanobiotechnology Department of the Institute of Biotechnology, Brandenburg University of Technology Cottbus-Senftenberg, Universitaetsplatz 1, Senftenberg 01968, Brandenburg, Germany.
Anal Chem. 2025 Jan 21;97(2):1160-1169. doi: 10.1021/acs.analchem.4c04181. Epub 2025 Jan 6.
Single nanoparticle (NP) cyclic voltarefractometry (CVR), realized as wide-field surface plasmon resonance microscopy (SPRM) in combination with potential cycling, has been proposed and applied to the in situ study of TiO NPs. Electrochemical activity of TiO is mainly observed outside the electrochemical stability window of water. Therefore, the response of individual anatase (a-TiO) and rutile (r-TiO) NPs adsorbed on a gold layer was studied in 0.25 M LiClO acetonitrile solutions. The use of acetonitrile allows us to exploit a much wider potential window compared to water, while due to the almost identical refractive index ( = 1.344 and 1.333 for acetonitrile and water, respectively), the conditions of the SPR are not changed. This greatly expands the variety of electrochemical reactions that can be studied by SPR techniques. Cyclic polarization of a-TiO and r-TiO NPs results in pronounced electrochemical and optical responses around -1.55 V and around -1.8 V vs Fc/Fc, respectively. This specific optoelectrochemical response allows them to be distinguished from other NPs. Based on this difference in characteristic potentials, a mixture of a-TiO and r-TiO NPs can be analyzed by CVR as well. The proposed correction algorithm compensates for the drift in the SPRM background caused by the accompanying formation of insoluble compounds and separates the optical response of the NPs out of the background. The results obtained in the study of this complex system demonstrate the capabilities of the developed analytical method. The CVR can be applied to the quantitative analysis of many other types of NPs in nonaqueous solutions, providing information on the electrochemical properties of each individual particle on the electrode surface.
单纳米颗粒（NP）循环伏安折光法（CVR），通过宽场表面等离子体共振显微镜（SPRM）结合电位循环实现，已被提出并应用于TiO NPs的原位研究。TiO的电化学活性主要在水的电化学稳定性窗口之外观察到。因此，在0.25 M LiClO乙腈溶液中研究了吸附在金层上的单个锐钛矿型（a-TiO）和金红石型（r-TiO）NP的响应。与水相比，使用乙腈可以利用更宽的电位窗口，而由于折射率几乎相同（乙腈和水分别为1.344和1.333），SPR的条件没有改变。这极大地扩展了可通过SPR技术研究的电化学反应的种类。a-TiO和r-TiO NP的循环极化分别在相对于Fc/Fc约-1.55 V和约-1.8 V处产生明显的电化学和光学响应。这种特定的光电化学响应使它们能够与其他NP区分开来。基于特征电位的这种差异，a-TiO和r-TiO NP的混合物也可以通过CVR进行分析。所提出的校正算法补偿了由伴随形成的不溶性化合物引起的SPRM背景中的漂移，并将NP的光学响应从背景中分离出来。在该复杂系统研究中获得的结果证明了所开发分析方法的能力。CVR可应用于非水溶液中许多其他类型NP的定量分析，提供有关电极表面每个单个颗粒电化学性质的信息。
