Benchmarking the Stability of Oxygen Evolution Reaction Catalysts: The Importance of Monitoring Mass Losses

Abstract

Because of the rising need for energy storage, potentially facilitated by electrolyzers, improvements to the catalysis of the oxygen evolution reaction (OER) become increasingly relevant. Standardized protocols have been developed for determining critical figures of merit, such as the electrochemical surface area, mass activity and specific activity. Even so, when new and more active catalysts are reported, the catalyst stability tends to play a minor role. In this work, we monitor corrosion on RuO2 and MnOx by combining the electrochemical quartz crystal microbalance (EQCM) with inductively coupled plasma mass spectrometry (ICP–MS). We show that a meaningful estimation of the stability cannot be achieved based on purely electrochemical tests. On the catalysts tested, the anodic dissolution current was four orders of magnitude lower than the total current. We propose that even if long‐term testing cannot be replaced, a useful evaluation of the stability can be achieved with short‐term tests by using EQCM or ICP–MS.

Toward the rational design of non-precious transition metal oxides for oxygen electrocatalysis

“…210,211 Short-term testing of long-term catalyst stability has been a particular challenge. However, Frydendal et al 212 recently demonstrated that while short-term chronopotentiometry and chronoamperometry measurements are not indicative of longterm performance stability, electrochemical quartz crystal microbalance (EQCM) and inductively coupled mass spectroscopy (ICP-MS) offer a meaningful alternative to longterm device testing. ICP-MS studies have confirmed that degradation of RuO2, 212 MnOx, 212 and SrRuO3 213 are due to anodic dissolution, forming transition metal species in solution.…”

“…However, Frydendal et al 212 recently demonstrated that while short-term chronopotentiometry and chronoamperometry measurements are not indicative of longterm performance stability, electrochemical quartz crystal microbalance (EQCM) and inductively coupled mass spectroscopy (ICP-MS) offer a meaningful alternative to longterm device testing. ICP-MS studies have confirmed that degradation of RuO2, 212 MnOx, 212 and SrRuO3 213 are due to anodic dissolution, forming transition metal species in solution. It is essential that new methods be further developed for characterizing dissolution mechanisms and identifying the relationships between catalyst stability and chemistry.…”

Activity and Stability of Electrochemically and Thermally Treated Iridium for the Oxygen Evolution Reaction

“…Other authors used chronoamperometry for 0.5 h 34 or chronopotentiometry for 15 h, 6 25 h 36 and 120 h. 5 Instead, investigation of the actual loss of active material directly during polarization can be very helpful to assess the stability on a long run. 37 Such data can be used for estimation of the electrodes end-of-life.…”

Cover Feature: Mechanistic Parameters of Electrocatalytic Water Oxidation on LiMn2O4 in Comparison to Natural Photosynthesis (ChemSusChem 22/2017)

“…During the later cycles,t he onseto ft he ring currents of LiMn 2 O 4 -carbon electrodes shiftedt oh igher voltages and might coincide with oxygen evolution as reported previously for electrodeposited Mn 3 + /4 + oxides. [56,57] Nonetheless, these currents were within the background and did not affect the interpretation of our results.…”