Dynamic methods for electrochemical gas sensors (DynaSens)

在固体电解质如YSZ上的电化学传感器结构的动态行为由各种动力学控制过程决定。气相扩散、分析物吸附、表面扩散、电极中以及固体电解质中的电荷转移和电荷传输、竞争催化反应、物种的储存和反应产物的解吸属于最重要的那些。最佳利用这些过程的新一代的电化学高温传感器具有很大的学术和技术兴趣。到目前为止，已经研究和开发了各种各样的新材料用于电位传感器、电流传感器、库仑传感器和阻抗传感器。通常，在恒定的分析物浓度下建立动力学或动力学控制的平衡，从而导致恒定的传感器信号。与之相反，最近出现的一个概念表明，电极极化偏离平衡的动态方法可以通过显着提高灵敏度，选择性和稳定性来实现新的应用，尽管它们联合收割机了上述测量原理。然而，它还不能被澄清如何在电极/传感器和气相之间的边界处的单个过程详细地支配动态响应。这些过程之间的相互依赖性以及电极材料、电极结构、电极设计和传感器设计也是未知的。因此，该项目的目标是针对深入的调查，结合动态电化学方法，如电位和电动脉冲极化，差分脉冲伏安法，阻抗谱，这些参数与气体交换性能和热表面的催化活性结合联合收割机。有了这些工具，应该可以通过将不同方法的结果相关联来定量描述建立动力学过程及其相互依赖性的基本信号。结果将被纳入一个模型，这将使不同应用的动态控制的电化学传感器的优化。两个申请人在高温传感器制备、材料表征和新电化学方法开发领域的丰富经验，使他们能够共同努力，从自然科学的理解出发，为动态高温气体传感器创造新的工程方法。

The dynamic behavior of electrochemical sensor structures on solid electrolytes like YSZ is determined by a variety of kinetically controlled processes. Gas phase diffusion, analyte adsorption, surface diffusion, charge transfer and charge transport in the electrode as well as in the solid electrolyte, competing catalytic reactions, storage of species, and desorption of reaction products belong to the most important ones. The optimum utilization of these processes for a new generation of electrochemical high-temperature sensors is of great academic and technical interest. Till now, a great variety of new materials has been investigated and developed for potentiometric, amperometric, coulometric, and impedimetric sensors. Typically thermodynamically or kinetically controlled equilibria are established at constant analyte concentrations leading consequently to a constant sensor signal. In contrast to, a concept that has recently emerged, indicates that dynamic methods of electrode polarization offside from equilibrium, can enable new applications by the significant improvement of sensitivity, selectivity and stability, despite they combine the above-mentioned measurement principles. However, it could not have been clarified yet how single processes at the boundary between electrode/sensor and gas phase govern the dynamic response in detail. The interdependencies among these processes as well as to electrode materials, electrode structure, and electrode design and sensor design are also unknown. Therefore, the goal of the project is directed towards profound investigations to combine these parameters with gas exchange properties and catalytic activities of hot surfaces in combination with dynamic electrochemical methods like potentio- and galvanodynamic pulse polarization, differential pulse voltammetry, and impedance spectroscopy. With these tools, it should be possible to describe the essential signal establishing kinetic processes and their interdependencies quantitatively by correlating the results of the different methods. The results will be incorporated into a model that will enable the optimization of dynamically controlled electrochemical sensors for different applications. The extensive experiences of both applicants in the fields of high-temperature sensor preparation, materials characterization and the development of new electrochemical methods enable a concerted work to create new engineering approaches for dynamic high-temperature gas sensors from a natural scientifically based comprehension.