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Author: Kriescher, Stefanie ×

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    Atomic layer deposition for efficient oxygen evolution reaction at Pt/Ir catalyst layers
    (Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2020) Schlicht, Stefanie; Percin, Korcan; Kriescher, Stefanie; Hofer, André; Weidlich, Claudia; Wessling, Matthias; Bachmann, Julien
    We provide a direct comparison of two distinct methods of Ti felt surface treatment and Pt/Ir electrocatalyst deposition for the positive electrode of regenerative fuel cells and vanadium-air redox flow batteries. Each method is well documented in the literature, and this paper provides a direct comparison under identical experimental conditions of electrochemical measurements and in identical units. In the first method, based on classical engineering, the bimetallic catalyst is deposited by dip-coating in a precursor solution of the salts followed by their thermal decomposition. In the alternative method, more academic in nature, atomic layer deposition (ALD) is applied to the felts after anodization. ALD allows for a controlled coating with ultralow noble-metal loadings in narrow pores. In acidic electrolyte, the ALD approach yields improved mass activity (557 A·g-1 as compared to 80 A·g-1 at 0.39 V overpotential) on the basis of the noble-metal loading, as well as improved stability. © 2020 Schlicht et al.
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    Microtubular Gas Diffusion Electrode Based on Ruthenium-Carbon Nanotubes for Ambient Electrochemical Nitrogen Reduction to Ammonia
    (Weinheim : Wiley-VCH, 2020) Wei, Xin; Vogel, Dominik; Keller, Laura; Kriescher, Stefanie; Wessling, Matthias
    The drawback of the energy-intensive Haber-Bosch process promotes the research and development of alternative ammonia (NH3) synthesis approaches. The electrochemical nitrogen (N2) reduction reaction (eNRR) may offer a promising method to produce NH3 independent of fossil-fuel-based hydrogen production. However, the low solubility and the low-efficiency mass transport of N2 in aqueous electrolytes are still among the challenges facing the feasibility of eNRR. Herein, we demonstrate a microtubular ruthenium-carbon nanotube gas diffusion electrode (Ru−CNT GDE), for the first time, applying it to electrochemical NH3 synthesis in an H-type cell under ambient conditions. The highest reported Ru-catalyzed NH3 yield rate of 2.1×10−9 mol/cm2 s and high faradaic efficiency of 13.5 % were achieved, showing the superior effect of Ru−CNT GDEs on the eNRR performance. This work provides a new approach for the design and fabrication of self-standing catalyst-loaded GDEs for eNRR. © 2020 The Authors. ChemElectroChem published by Wiley-VCH GmbH