A Guide to Electrocatalyst Stability Using Lab-Scale Alkaline Water Electrolyzers

Redefining the Stability of Water Oxidation Electrocatalysts: Insights from Materials Databases and Machine Learning

“…Although studies often focus on highly alkaline or acidic conditions, this consideration is far from trivial, given the observable shifts in local pH and the variable operational conditions characteristic of actual water electrolysis systems. , Therefore, it is essential to consider the dynamic environment when testing water-splitting electrocatalysts. Figure shows the Pourbaix diagrams of Co 2 P and CoTe compositions to illustrate some notorious characteristics of the stability of TM X-ides.…”

“…Moving forward, researchers must design experiments appropriately, including selecting the electrochemical conditioning method, considering potential impurity incorporation, and following recommendations to conduct electrochemical measurements appropriately. ,,− Comprehensive details regarding conditioning, testing, and characterization conditions should be provided to improve reproducibility within the field. Importantly, claims of activity and stability should only be made after a stable local equilibrium of the active phase has been achieved after conditioning . It is essential to distinguish between conditioning and long-term testing; conditioning seeks to establish a stable “baseline” phase of the material, while long-term testing challenges this phase with prolonged or variable currents.…”

“…Previous works have linked substrate effects to OER activity enhancement in transition metal oxyhydroxide catalysts. − More experimental and computational studies are necessary to explore the role of these extrinsic properties on the performance and transformation of TM X-ides. Furthermore, studies could explore how postreconstruction morphologies affect bubble removal, which is crucial for industrial water electrolysis, along with the reconstruction’s impact on mechanical stability, surface roughness, and corrosion over time. ,, Investigations at higher and fluctuating currents are also pertinent …”

The Rationale for a Standardized Testing Protocol for Anion Exchange Membrane Water Electrolyzers

“…Marquez et al advocated for the improvement of testing protocols and suggested the best practices for electrolyte preparation, removing Fe impurities, electrolyte standardization, determining composition by ICP-MS analysis, statistical quality control, and electrochemical testing, to validate the quality of alkaline electrolytes used in electrocatalytic systems. Additionally, they provided a general standard protocol for evaluating the electrocatalytic stability of lab-scale alkaline electrolyzers and a guideline for troubleshooting device operation and data acquisition …”

“…While this highlights beneficial conditions for efficient hydrogen production, the translation for the devices suitability as a commercial technology is difficult to decipher. Marquez et al emphasized the importance of shifting the focus from achieving high performances, using impractical condition during testing, to understand the physical phenomena influencing cell behavior under realistic operational conditions. By prioritizing realistic testing conditions, researchers can bridge the intrinsic properties of materials with the electrolzer’s performance under similar environments representative of industrial usage .…”