A wide range of materials, including metals, alloys, and oxides, can act as catalysts in electrocatalysis, a field that studies how certain materials can speed up chemical reactions driven by electricity. Many sustainable technologies, such as green hydrogen production and the conversion of CO₂ emissions into valuable industrial products, are based on electrocatalysis. However, identifying the most effective catalysts for each reaction remains a significant challenge, due to the absence of clear, widely accepted criteria for fair comparison.

To address this issue, a new perspective article by ICN2 researchers provides a clearer conceptual framework for comparing catalyst performance across studies. The work clarifies key concepts and makes the assumptions behind commonly used normalisation strategies explicit. The study, published in ACS Energy Letters, was authored by ICREA Prof. María Escudero-Escribano and Dr Jon Bjarke Valbæk Mygind, both from the ICN2 NanoESC Group, in collaboration with Dr Marcel J. Rost (Leiden University).

Looking beyond traditional concepts

The study shows that there is no single universally valid normalisation strategy for comparing catalyst performance across studies. Instead, it provides a framework that clarifies how different normalisation approaches can be used consistently and transparently. The Perspective distinguishes three approaches to activity normalization.  Real surface area (RSA), which describes an electrode's total physical surface, and electrochemically active surface area (ECSA), which reflects the portion of that surface that participates in a specific reaction under specific conditions. Importantly, ECSA is not a fixed property of a material; it can change depending on how and where it is measured. A third approach is active site counting, which avoids geometric surface-area assumptions and offers a direct route to intrinsic activity normalisation.

The authors stress that progress in catalyst development depends not only on discovering new materials, but also on comparing them fairly. Clear definitions and explicit assumptions are essential to ensure that reported improvements reflect real advances rather than differences in methodology. By enabling fairer and more consistent comparison across studies, the framework strengthens the reproducibility of catalyst research. This, in turn, supports the development of key technologies, from clean energy conversion and storage to more sustainable chemical production.

Reference article:
Valbæk Mygind, JB; Rost, MJ; Escudero-Escribano, M. The Hidden Complexities of Electrochemically Active Surface Area Measurements. ACS Energy Letters. (2026). https://doi.org/10.1021/acsenergylett.5c04204