Physical Chemistry, TU Dresden, Zellescher Weg 19, 01069 Dresden, Germany.
Institute for Computational Physics (ICP), Allmandring 3, 70569 Stuttgart, Germany.
J Am Chem Soc. 2021 Oct 20;143(41):17015-17022. doi: 10.1021/jacs.1c06400. Epub 2021 Sep 15.
Micromotors are propelled by a variety of chemical reactions, with most of them being of catalytic nature. There are, however, systems based on redox reactions, which show clear benefits for efficiency. Here, we broaden the spectrum of suitable reactions to galvanic exchange processes, or an electrochemical replacement of a solid metal layer with dissolved ionic species of a more noble metal. We study the details of motility and the influence of different reaction parameters to conclude that these galvanophoretic processes circumvent several steps that lose efficiency in catalytic micromotors. Furthermore, we investigate the chemical process, the charge, and flow conditions that lead to this highly efficient new type of active motility. Toward a better understanding of the underlying processes, we propose an electrokinetic model that we numerically solve via finite elements.
微马达通过各种化学反应来推动，其中大多数是催化性质的。然而，也有基于氧化还原反应的系统，它们在效率方面表现出明显的优势。在这里，我们将适用的反应范围扩大到了电交换过程，或者是电化学取代更贵金属的溶解离子物种的固态金属层。我们研究了运动的细节以及不同反应参数的影响，得出结论，这些电泳过程避免了催化微马达中效率降低的几个步骤。此外，我们研究了导致这种高效新型主动运动的化学过程、电荷和流动条件。为了更好地理解潜在的过程，我们提出了一个电动模型，并通过有限元法对其进行数值求解。
