The performance of platinum group metal-free (PGM-free) catalyst layers suffers from mass transport limitations owing to the thickness required to achieve sufficiently high loading to match the performance of the Pt-based electrodes. A more detailed understanding of the PGM-free electrode structure is of a great importance to further improve their performance, but the nanoscale structure presents a challenge. In the present study, a non-PGM catalyst was synthesized by the sacrificial support method, and the electrospraying technique was used to fabricate catalyst layer electrodes. Electrodes with substantially different structural properties were obtained by varying the electrospraying parameters such as ink flow rate and the distance between the needle and the substrate. A wide range of structural properties of these non-PGM electrodes were experimentally measured, including thickness, porosity, pore size distribution, specific surface area, and the mass transport characteristics in the form of tortuosity. In general, the non-PGM catalyst layers fabricated by the electrospraying technique had much lower tortuosity than conventional catalyst layers due to a combination of highly porous structure and larger interagglomerate pores reducing the impact of the Knudsen effect. Geometric tortuosity was also obtained by adjusting the measured effective diffusivity values to remove the Knudsen effect, and it was found that electrosprayed and conventional layers follow a similar trend with porosity.

由于实现足够高的负载以匹配基于Pt的电极的性能所需的厚度，无铂族金属（无PGM）催化剂层的性能受到传质限制。对不含PGM的电极结构的更详细的了解对于进一步提高其性能非常重要，但是纳米级结构却是一个挑战。在本研究中，通过牺牲载体方法合成了非PGM催化剂，并采用电喷雾技术制备了催化剂层电极。通过改变电喷雾参数（例如墨水流速和针头与基材之间的距离）可获得具有实质上不同的结构特性的电极。通过实验测量了这些非PGM电极的各种结构特性，包括厚度，孔隙率，孔径分布，比表面积以及曲折形式的质量传输特性。通常，通过电喷雾技术制造的非PGM催化剂层的曲折度比常规催化剂层低得多，这归因于高度多孔的结构和较大的团聚体孔的结合，从而降低了克努森效应的影响。通过调节测得的有效扩散率值以消除克努森效应也可获得几何曲折度，并且发现电喷涂层和常规层的孔隙率趋势相似。以及曲折形式的大众运输特征。通常，通过电喷雾技术制造的非PGM催化剂层的曲折度比常规催化剂层低得多，这归因于高度多孔的结构和较大的团聚体孔的结合，从而降低了克努森效应的影响。通过调节测得的有效扩散率值以消除克努森效应也可获得几何曲折度，并且发现电喷涂层和常规层的孔隙率趋势相似。以及曲折形式的大众运输特征。通常，通过电喷雾技术制造的非PGM催化剂层的曲折度比常规催化剂层低得多，这归因于高度多孔的结构和较大的团聚体孔的结合，从而降低了克努森效应的影响。通过调节测得的有效扩散率值以消除克努森效应也可获得几何曲折度，并且发现电喷涂层和常规层的孔隙率趋势相似。通过电喷雾技术制造的非PGM催化剂层的曲折度比常规催化剂层低得多，这是由于高度多孔的结构和较大的团聚体孔的结合降低了克努森效应的影响。通过调节测得的有效扩散率值以消除克努森效应也可获得几何曲折度，并且发现电喷涂层和常规层的孔隙率趋势相似。通过电喷雾技术制造的非PGM催化剂层的曲折度比常规催化剂层低得多，这是由于高度多孔的结构和较大的团聚体孔的结合降低了克努森效应的影响。通过调节测得的有效扩散率值以消除克努森效应也可获得几何曲折度，并且发现电喷涂层和常规层的孔隙率趋势相似。