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.

Pt dissolution has already been intensively studied in aqueous model systems and many mechanistic insights have been gained. Nevertheless,t ransfer of new knowledge to realworld fuel cell systems is still as ignificant challenge.T oc lose this gap,w ep resent an ovel in situ method combining ag as diffusion electrode (GDE) half-cell with inductively coupled plasma mass spectrometry (ICP-MS). With this setup,P t dissolution in realistic catalyst layers and the transport of dissolved Pt species through Nafion membranes were evaluated directly.W eo bserved that 1) specific Pt dissolution increased significantly with decreasing Pt loading, 2) in comparison to experiments on aqueous model systems with flowc ells,t he measured dissolution in GDE experiments was considerably lower,a nd 3) by adding am embrane onto the catalyst layer,Ptdissolution was reduced even further.All these phenomena are attributed to the varying mass transport conditions of dissolved Pt species,i nfluencing re-deposition and equilibrium potential.

The electrochemical activity of modern Fe–N–C electrocatalysts in alkaline media is on par with that of platinum. For successful application in fuel cells (FCs), however, also high durability and longevity must be demonstrated. Currently, a limited understanding of degradation pathways, especially under operando conditions, hinders the design and synthesis of simultaneously active and stable Fe–N–C electrocatalysts. In this work, using a gas diffusion electrode half-cell coupled with inductively coupled plasma mass spectrometry setup, Fe dissolution is studied under conditions close to those in FCs, that is, with a porous catalyst layer (CL) and at current densities up to −125 mA·cm–2. Varying the rate of the oxygen reduction reaction (ORR), we show a remarkable linear correlation between the Faradaic charge passed through the electrode and the amount of Fe dissolved from the electrode. This finding is rationalized assuming that oxygen reduction and Fe dissolution reactions are interlinked, likely through a common intermediate formed during the Fe redox transitions in Fe species involved in the ORR, such as FeN x C y and Fe3C@N–C. Moreover, such a linear correlation allows the application of a simple metricS-numberto report the material’s stability. Hence, in the current work, a powerful tool for a more applied stability screening of different electrocatalysts is introduced, which allows on the one hand fast performance investigations under more realistic conditions, and on the other hand a more advanced mechanistic understanding of Fe–N–C degradation in CLs.

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Bipolar membrane|electrode interface water electrolyzers (BPEMWE) were found to outperform a proton exchange membrane (PEM) water electrolyzer reference in a similar membrane electrode assembly (MEA) design based on individual porous...

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A fast and facile pulse combustion (PC) method that allows for the continuous production of multigram quantities of high-metal-loaded and highly uniform supported metallic nanoparticles (SMNPs) is presented. Namely, various metal on carbon (M/C) composites have been prepared by using only three feedstock components: water, metal–salt, and the supporting material. The present approach can be elegantly utilized also for numerous other applications in electrocatalysis, heterogeneous catalysis, and sensors. In this study, the PC-prepared M/C composites were used as metal precursors for the Pt NPs deposition using double passivation with the galvanic displacement method (DP method). Lastly, by using thin-film rotating disc electrode (TF-RDE) and gas-diffusion electrode (GDE) methodologies, we show that the synergistic effects of combining PC technology with the DP method enable production of superior intermetallic Pt–M electrocatalysts with an improved oxygen reduction reaction (ORR) performance when compared to a commercial Pt–Co electrocatalyst for proton exchange membrane fuel cells (PEMFCs) application.