Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts under high mass transport conditions, while maintaining the simplicity of rotating disk electrode (RDE) setups. In contrast to experimental RDE protocols, for investigations using GDE setups only few systematic studies have been performed. In literature, different GDE arrangements were demonstrated, for example, with and without an incorporated proton exchange membrane. Herein, we chose a membrane‐GDE approach for a comparative RDE–GDE study, where we investigate several commercial standard Pt/C fuel cell catalysts with respect to the oxygen reduction reaction (ORR). Our results demonstrate both the challenges and the strengths of the new fuel cell catalyst testing platform. We highlight the analysis and the optimization of catalyst film parameters. That is, instead of focusing on the intrinsic catalyst ORR activities that are typically derived in RDE investigations, we focus on parameters, such as the catalyst ink recipe, which can be optimized for an individual catalyst in a much simpler manner as compared to the elaborative membrane electrode assembly (MEA) testing. In particular, it is demonstrated that ∼50% improvement in ORR performance can be reached for a particular Pt/C catalyst by changing the Nafion content in the catalyst layer. The study therefore stresses the feasibility of the GDE approach used as an intermediate “testing step” between RDE and MEA tests when developing new fuel cell catalysts.

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Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts. As compared to the state-of-the-art in fundamental research, i.e., rotating disk electrode (RDE) measurements, GDE measurements offer several advantages. Most importantly mass transport limitations, inherent to RDE measurements are avoided. In a GDE setup the reactant, e.g., oxygen gas, is not dissolved into a liquid electrolyte but distributed through a gas diffusion layer (GDL), as it is actually the case in fuel cells. Consequently, much higher current densities can be achieved, and the catalysts can be studied in a wider and more relevant potential range. Furthermore, direct contact to a liquid electrolyte can be avoided and elevated temperatures can be employed in a straight-forward manner. However, the use of GDE setups also comes with some challenges. The determined performance is not strictly related to the catalyst itself (intrinsic activity), but also to the quality of the catalyst film preparation. Therefore, it might be even more important than in RDE testing to develop standardized procedures to prepare catalysts inks and films that can be reproduced effortlessly in research laboratories for fundamental and applied experimentation. To develop such standardized testing protocols, we present a comparative RDE – GDE study, where we investigate several commercial standard Pt/C fuel cell catalysts with respect to the oxygen reduction reaction (ORR). The study highlights the strengths of the GDE approach as an intermediate “testing step” between RDE and membrane electrode assembly (MEA) tests when developing new fuel catalysts.

Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts. As compared to the state-of-the-art in fundamental research, i.e., rotating disk electrode (RDE) measurements, GDE measurements offer several advantages. Most importantly mass transport limitations, inherent to RDE measurements are avoided. In a GDE setup the reactant, e.g., oxygen gas, is not dissolved into a liquid electrolyte but distributed through a gas diffusion layer (GDL), as it is actually the case in fuel cells. Consequently, much higher current densities can be achieved, and the catalysts can be studied in a wider and more relevant potential range. Furthermore, direct contact to a liquid electrolyte can be avoided and elevated temperatures can be employed in a straight-forward manner. However, the use of GDE setups also comes with some challenges. The determined performance is not strictly related to the catalyst itself (intrinsic activity), but also to the quality of the catalyst film preparation. Therefore, it might be even more important than in RDE testing to develop standardized procedures to prepare catalysts inks and films that can be reproduced effortlessly in research laboratories for fundamental and applied experimentation. To develop such standardized testing protocols, we present a comparative RDE – GDE study, where we investigate several commercial standard Pt/C fuel cell catalysts with respect to the oxygen reduction reaction (ORR). The study highlights the strengths of the GDE approach as an intermediate “testing step” between RDE and membrane electrode assembly (MEA) tests when developing new fuel catalysts.

No abstract