Min Kyungwhan, Al Munsur Abu Zafar, Paek Sae Yane, Jeon Soomin, Lee So Young, Kim Tae-Hyun
Organic Material Synthesis Laboratory, Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea.
Research Institute of Basic Sciences, Core Research Institute, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, South Korea.
ACS Appl Mater Interfaces. 2023 Mar 29;15(12):15616-15624. doi: 10.1021/acsami.3c01289. Epub 2023 Mar 16.
Proton exchange membrane water electrolysis (PEMWE) generates oxygen and hydrogen at the anode and cathode, respectively, by conducting protons generated at the anode to the cathode through a proton exchange membrane (PEM). The performance of PEMWE can be improved with faster catalytic reactions at each electrode; thus, the development of a PEM with excellent ionic conductivity and physicochemical stability is essential. Nafion, a type of perfluoro-sulfonic acid polymer, is the most widely used PEM material. However, despite its excellent conductivity and chemical stability, it exhibits high hydrogen permeability due to its structural characteristics. Quantum dots (QDs) have a hydrophilic functional group that can act as an ion conductor and are extremely compatible with the hydrophilic cluster of Nafion due to their characteristic nanosized structure. In this study, various compositions of N-doped carbon quantum dots (CQDs) containing hydrophilic functional groups were coated on a Nafion-212 membrane. The resulting series of CQD-coated Nafion membranes exhibited improvements in morphology and ionic conductivity as well as reductions in hydrogen permeability. In particular, the Nafion membrane coated with 0.75 wt % of N-doped CQD (CQD-cNafion-0.75) exhibited improved mechanical properties and higher oxidation stability compared to Nafion-212. It also displayed higher ionic conductivity of 240.3 mS cm at 80 °C and reduced hydrogen permeability (about 10% reduction) compared to Nafion-212. In addition, the performance of single-cell PEMWE using the CQD-cNafion-0.75 membrane was found to be approximately 1.2 times higher than Nafion-212.
质子交换膜水电解（PEMWE）通过质子交换膜（PEM）将阳极产生的质子传导至阴极，分别在阳极和阴极产生氧气和氢气。通过加快每个电极上的催化反应，可以提高PEMWE的性能；因此，开发具有优异离子导电性和物理化学稳定性的PEM至关重要。Nafion是一种全氟磺酸聚合物，是使用最广泛的PEM材料。然而，尽管它具有优异的导电性和化学稳定性，但由于其结构特性，它表现出较高的氢渗透性。量子点（QD）具有可作为离子导体的亲水性官能团，并且由于其特征性的纳米尺寸结构，与Nafion的亲水簇具有极高的相容性。在本研究中，将含有亲水性官能团的各种组成的氮掺杂碳量子点（CQD）涂覆在Nafion-212膜上。所得的一系列CQD涂覆的Nafion膜在形态和离子导电性方面有所改善，同时氢渗透性降低。特别是，涂覆有0.75 wt%氮掺杂CQD（CQD-cNafion-0.75）的Nafion膜与Nafion-212相比，机械性能得到改善，氧化稳定性更高。在80°C时，它还显示出240.3 mS cm的更高离子导电性，与Nafion-212相比，氢渗透性降低（约降低10%）。此外，发现使用CQD-cNafion- O.75膜的单电池PEMWE性能比Nafion-212高约1.2倍。
