Automated high-throughput activity and stability screening of electrocatalysts

Abstract

Common high-throughput (HT) approaches rapidly assess the activity of electrocatalyst libraries toward electrochemical conversion reactions. The short time regime on which individual measurements are performed creates a false perception of catalyst durability, masking the true catalyst performance by the omission of detailed stability assessments during HT campaigns. Here, an automated scanning flow cell coupled to an inductively coupled plasma mass spectrometer was developed, allowing a simultaneous HT determination of the catalyst activity and stability. Fe-Ni and Fe-Ni-Co oxide libraries were automatically synthesized by a custom-programmed pipetting robot and examined as an oxygen evolution catalyst in neutral media, the advancement of which remains a great challenge. Ni-rich compositions in Fe-Ni oxides show higher activity but also significant catalyst loss due to the major Ni dissolution, which triggers Fe dissolution. Co-rich compositions in Fe-Ni-Co oxides attain the best synergy between activity and stability. • Automated scanning flow cell linked to inductively coupled plasma mass spectrometer • High-throughput platform allowing simultaneous activity and stability measurement • Neutral OER activity and in situ stability of Fe-Ni and Fe-Ni-Co oxides libraries • Automated synthesis using liquid-handling robot Transition metal oxides are an abundant and low-cost material class suitable as catalyst for electrochemical conversion reactions. The vast space of possible elemental combinations to construct such catalysts necessitates the use of accelerated laboratory experiments to rapidly screen material libraries for compositions with suitable properties. Activity and stability parameters of an electrocatalyst are key metrics that are decisive for their consideration as a promising candidate. Screening both performance indicators simultaneously in a high-throughput manner is crucial. The automation of an electrochemical flow cell coupled to an inductively coupled plasma mass spectrometer allows the rapid assessment of key catalyst parameters at the same time. Accelerating the material discovery exploration can help advancing key scientific areas and scientific knowledge needed for the energy transition of the society. High-throughput screening of multicompositional catalysts for electrocatalytic reactions significantly accelerates material development and discovery. While the activity of such catalyst libraries is the prime target of high-throughput investigations, the stability is often neglected, which plays a crucial role in defining the performance of electrocatalysts. The development of an automated platform involving a scanning flow cell coupled to an inductively coupled plasma mass spectrometer allows for a rapid measurement of the catalyst activity and stability simultaneously.