Kovács Miklós Márton, Fritsch Birk, Lahn Leopold, Bachmann Julien, Kasian Olga, Mayrhofer Karl J J, Hutzler Andreas, Dworschak Dominik
Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IET-2), 91058 Erlangen, Germany.
Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Chemical and Biological Engineering, 91058 Erlangen, Germany.
ACS Appl Mater Interfaces. 2024 Oct 2;16(39):52179-52190. doi: 10.1021/acsami.4c07831. Epub 2024 Sep 18.
The enhanced utilization of noble metal catalysts through highly porous nanostructures is crucial to advancing the commercialization prospects of proton exchange membrane water electrolysis (PEMWE). In this study, hierarchically structured IrO-based nanofiber catalyst materials for acidic water electrolysis are synthesized by electrospinning, a process known for its scalability and ease of operation. A calcination study at various temperatures from 400 to 800 °C is employed to find the best candidates for both electrocatalytic activity and stability. Morphology, structure, phase, and chemical composition are investigated using a scale-bridging approach by SEM, TEM, XRD, and XPS to shed light on the structure-function relationship of the thermally prepared nanofibers. Activity and stability are monitored by a scanning flow cell (SFC) coupled with an inductively coupled plasma mass spectrometer (ICP-MS). We evaluate the dissolution of all metals potentially incorporated into the final catalyst material throughout the synthesis pathway. Despite the opposite trend of performance and stability, the present study demonstrates that an optimum between these two aspects can be achieved at 600 °C, exhibiting values that are 1.4 and 2.4 times higher than those of the commercial reference material, respectively. The dissolution of metal contaminations such as Ni, Fe, and Cr remains minimal, exhibiting no correlation with the steps of the electrochemical protocol applied, thus exerting a negligible influence on the stability of the nanofibrous catalyst materials. This work demonstrates the scalability of electrospinning to produce nanofibers with enhanced catalyst utilization and their testing by SFC-ICP-MS. Moreover, it illustrates the influence of calcination temperature on the structure and chemical composition of the nanofibers, resulting in outstanding electrocatalytic performance and stability compared to commercial catalyst materials for PEMWE.
通过高度多孔的纳米结构提高贵金属催化剂的利用率对于推动质子交换膜水电解（PEMWE）的商业化前景至关重要。在本研究中，通过静电纺丝合成了用于酸性水电解的具有分层结构的IrO基纳米纤维催化剂材料，静电纺丝是一种以其可扩展性和操作简便性而闻名的工艺。采用在400至800°C的不同温度下进行的煅烧研究，以找到电催化活性和稳定性方面的最佳候选材料。使用SEM、TEM、XRD和XPS等跨尺度方法研究形态、结构、相和化学成分，以阐明热制备纳米纤维的结构-功能关系。通过与电感耦合等离子体质谱仪（ICP-MS）联用的扫描流动池（SFC）监测活性和稳定性。我们评估了在整个合成途径中可能掺入最终催化剂材料的所有金属的溶解情况。尽管性能和稳定性呈现相反的趋势，但本研究表明，在600°C时可以在这两个方面实现最佳平衡，其表现分别比商业参考材料高1.4倍和2.4倍。Ni、Fe和Cr等金属污染物的溶解量保持在最低水平，与所应用的电化学协议步骤无关，因此对纳米纤维催化剂材料的稳定性影响可忽略不计。这项工作展示了静电纺丝在生产具有更高催化剂利用率的纳米纤维方面的可扩展性以及通过SFC-ICP-MS对其进行测试的能力。此外，它还说明了煅烧温度对纳米纤维结构和化学成分的影响，与用于PEMWE的商业催化剂材料相比，具有出色的电催化性能和稳定性。
