Oxygen reduction performance measurements: Discrepancies against benchmarks

Oxygen electrocatalysis is crucial for renewable energy conversion and storage technologies. Specifically for proton exchange membrane fuel cells (PEMFCs), oxygen reduction reaction (ORR) is the primary reaction that determines performance and costs. The ORR activity and durability are commonly assessed using a rotating disk electrode (RDE). However, there are numerous inconsistencies in the RDE measurements among researchers when comparing newly developed ORR catalysts to state-of-the-art ones. These inconsistencies in activity and durability evaluation and deviations from standard protocols result in irreproducible screening and benchmarking of electrocatalysts. Despite the fact that the US Department of Energy has established and regularly revises the standard protocols, many reported studies do not adhere to these guidelines. This perspective aims to draw attention to the discrepancies in ORR activity and stability measurements at RDE as primary screening and emphasizes implementing the mandatory standard for a meaningful comparison of ORR activity and durability. We intend to emphasize the use of available ORR test standards ubiquitously for more accurate comparisons and accelerate the development of fuel cell catalysts.