In this work, the PtNiRu/SnO₂ nanocatalyst demonstrates the highest specific activity toward ethanol oxidation, despite having the lowest electrochemically active surface area (ECSA) among the tested samples. This raises a concern regarding the reliability of ECSA-based normalization in assessing catalytic performance, especially when factors such as SnO₂ coverage or aggregation may significantly reduce the accessible platinum surface area. Wouldn’t this potentially lead to an overestimation of the intrinsic activity of the catalyst? In such cases, wouldn’t it be more balanced to complement ECSA-normalized values with mass activity or geometric current density to ensure a fairer and more accurate comparison across different catalyst formulations?
