Institute of Materials Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria.
Phys Chem Chem Phys. 2021 Jul 7;23(26):14457-14464. doi: 10.1039/d1cp01491a.
The electrochemical behaviour of nanoporous gold modified with self-assembled monolayers is investigated with regard to its point of zero charge (pzc) and proton transfer reaction. Due to their high surface-to-volume ratio and conductivity, nanoporous electrodes represent promising materials for numerous applications, including the immobilization of biomolecules in biotechnology and biosensing. Therefore, the fundamental understanding and controllability of the surface state of the electrode is essential. To achieve a precise surface charge control, nanoporous gold (npAu) is modified with self-assembled monolayers (SAMs) of different lengths (3-mercaptopropionic acid (MPA) and 16-mercaptohexadecanoic acid (MHDA)). Cyclic voltammetry and impedance spectroscopy are used to determine the pzc. The most distinct pzc, and thus the most precise charge control, is found for the long-chain MHDA. Subsequently, the proton transfer reaction was investigated as a function of pH and scan rate. The observed protonation/deprotonation reaction was qualitatively well in line with the literature for planar gold electrodes, albeit the fraction of electrochemical controllable SAMs increased by a factor of 10 compared to planar electrodes indicating attractive application potential.
采用自组装单分子层对纳米多孔金进行修饰，研究了其零电荷点（pzc）和质子传递反应的电化学行为。由于纳米多孔电极具有高的表面积与体积比和导电性，因此在包括生物技术和生物传感中生物分子固定化等众多应用中具有广阔的应用前景。因此，对电极表面状态的基本理解和可控性至关重要。为了实现精确的表面电荷控制，用不同长度的自组装单分子层（巯基丙酸（MPA）和十六硫醇（MHDA））对纳米多孔金（npAu）进行了修饰。采用循环伏安法和阻抗谱法测定了 pzc。对于长链 MHDA，发现了最明显的 pzc，因此可以实现最精确的电荷控制。随后，研究了质子传递反应随 pH 值和扫描速率的变化。观察到的质子化/去质子化反应与平面金电极的文献定性吻合，尽管与平面电极相比，电化学可控 SAMs 的分数增加了 10 倍，表明其具有吸引力的应用潜力。
