Evaluating Electrocatalysts at Relevant Currents in a Half-Cell: The Impact of Pt Loading on Oxygen Reduction Reaction

Abstract

In this work gas diffusion electrode (GDE) half-cells experiments are proposed as powerful tool in fuel cell catalyst layer evaluation as it is possible to transfer the advantages of fundamental methods like thin-film rotating disk electrode (TF-RDE) such as good comparability of results, dedicated elimination of undesired parameters etc. to relevant potential ranges for fuel cell applications without mass transport limitations. With the developed setup and electrochemical protocol, first experiments on different Pt/C loadings confirm excellent reproducibility. Thereby mass-specific current densities up to 30 A mg Pt −1 at 0.6 V vs. RHE are achieved. From a methodological perspective, good comparability to single cell measurements is obtained after theoretical corrections for temperature and concentration effects. In comparison to previous studies with GDE half-cells, polarization curves without severe mass transport limitations are recorded in a broad potential window. All these achievements indicate that the proposed method can be an efficient tool to bridge the gap between TF-RDE and single cell experiments by providing fast and dedicated insights into the effects of catalyst layers on oxygen reduction reaction performance. This method will enable straightforward and efficient optimization of catalyst layer composition and structure, especially for novel catalysts, thereby contributing to the performance enhancements of fuel cells with reduced Pt loading.

Platinum Dissolution in Realistic Fuel Cell Catalyst Layers

“…Hence, Pt nanoparticles are in direct contact with acidic aqueous media. However, in GDE experiments, the catalyst is not completely flooded (Figure 5, bottom) as was shown in previous half‐cell experiments by achieving oxygen reduction reaction (ORR) current densities of up to 2 A cm −2 [15b,d, 16] . Thus, dissolved Pt species can only be transported out of the catalyst layer into the liquid electrolyte via the ionomer.…”

“…[6c, 14] Gas diffusion electrode (GDE) half-cell setups have been proposed as as uitable tool to bridge the gap between fundamental electrochemical catalyst evaluation and applied fuel cell research. [15] In this work, we extend this method for fundamental catalyst dissolution studies.C oupling aG DE half-cell [15d, 16] to an ICP-MS ( Figure 1) we-for the first time reported in the literature-describe time-resolved and direct measurements of Pt dissolution in realistic catalyst layers and through Nafion membranes.W ith this novel technique,t he impact of catalyst loading and Nafion membrane thickness on Pt dissolution in GDEs is investigated. Thereby,new insights into the mobility of Pt ions within Nafion and its impact on Pt dissolution could be revealed.…”

“…In this work, we extend this method for fundamental catalyst dissolution studies. Coupling a GDE half‐cell [15d, 16] to an ICP‐MS (Figure 1) we—for the first time reported in the literature—describe time‐resolved and direct measurements of Pt dissolution in realistic catalyst layers and through Nafion membranes. With this novel technique, the impact of catalyst loading and Nafion membrane thickness on Pt dissolution in GDEs is investigated.…”

Engineering the Electrochemical Interface of Oxygen Reduction Electrocatalysts with Ionic Liquids: A Review

“…Some prominent examples of such setups are the floating electrode developed by Kucernak and coworkers [ 150 ] and the gas diffusion electrodes realized by Arenz and coworkers [ 151 ] or Cherevko and coworkers. [ 152 ]…”

Elucidating Pt-Based Nanocomposite Catalysts for the Oxygen Reduction Reaction in Rotating Disk Electrode and Gas Diffusion Electrode Measurements

“…In Pt-based alloy catalysts, both the addition of Ir and Au is reported to improve the ORR performance [15,16]. The performance of the nanocomposite catalysts is investigated in conventional rotating disk electrode (RDE) measurements [13,17,18] as well as in recently introduced gas diffusion electrode (GDE) measurements [19][20][21][22][23][24][25] that in contrast to the RDE measurements provide realistic catalyst loadings as well as realistic mass transport conditions.…”