TY - JOUR

T1 - Sputtered Platinum Thin-films for Oxygen Reduction in Gas Diffusion Electrodes

T2 - A Model System for Studies under Realistic Reaction Conditions

AU - Sievers, Gustav

AU - Jensen, Anders W.

AU - Brüser, Volker

AU - Arenz, Matthias

AU - Escudero Escribano, Maria

PY - 2019

Y1 - 2019

N2 - The development of catalysts for the oxygen reduction reaction in low-temperature fuel cells depends on efficient and accurate electrochemical characterization methods. Currently, two primary techniques exist: rotating disk electrode (RDE) measurements in half-cells with liquid electrolyte and single cell tests with membrane electrode assemblies (MEAs). While the RDE technique allows for rapid catalyst benchmarking, it is limited to electrode potentials far from operating fuel cells. On the other hand, MEAs can provide direct performance data at realistic conditions but require specialized equipment and large quantities of catalyst, making them less ideal for early-stage development. Using sputtered platinum thin-film electrodes, we show that gas diffusion electrode (GDE) half-cells can be used as an intermediate platform for rapid benchmarking at fuel-cell relevant current densities (~1 A cm−2). Furthermore, we demonstrate how different parameters (loading, electrolyte concentration, humidification, and Nafion membrane) influence the performance of unsupported platinum catalysts. The specific activity could be measured independent of the applied loading at potentials down to 0.80 VRHE reaching a value of 0.72 mA cm−2 at 0.9 VRHE in the GDE. By comparison with RDE measurements and Pt/C measurements, we establish the importance of catalyst characterization under realistic reaction conditions.

AB - The development of catalysts for the oxygen reduction reaction in low-temperature fuel cells depends on efficient and accurate electrochemical characterization methods. Currently, two primary techniques exist: rotating disk electrode (RDE) measurements in half-cells with liquid electrolyte and single cell tests with membrane electrode assemblies (MEAs). While the RDE technique allows for rapid catalyst benchmarking, it is limited to electrode potentials far from operating fuel cells. On the other hand, MEAs can provide direct performance data at realistic conditions but require specialized equipment and large quantities of catalyst, making them less ideal for early-stage development. Using sputtered platinum thin-film electrodes, we show that gas diffusion electrode (GDE) half-cells can be used as an intermediate platform for rapid benchmarking at fuel-cell relevant current densities (~1 A cm−2). Furthermore, we demonstrate how different parameters (loading, electrolyte concentration, humidification, and Nafion membrane) influence the performance of unsupported platinum catalysts. The specific activity could be measured independent of the applied loading at potentials down to 0.80 VRHE reaching a value of 0.72 mA cm−2 at 0.9 VRHE in the GDE. By comparison with RDE measurements and Pt/C measurements, we establish the importance of catalyst characterization under realistic reaction conditions.

U2 - 10.3390/surfaces2020025

DO - 10.3390/surfaces2020025

M3 - Journal article

VL - 2

SP - 336

EP - 348

JO - Surfaces

JF - Surfaces

SN - 1188-2492

IS - 2

ER -