A Rising Mismatch between System Complexity, Characterization, and Theory in Electrocatalysis: Challenges and Solutions

Electrocatalytic systems are enormously challenging to understand. Nevertheless, the complexity of systems reported in the literature constantly increases, with frequent reports on heterostructured electrodes containing multiple interfaces. As current electrochemical and analytical methods can hardly meet this complexity, fundamental catalytic aspects often remain elusive, e.g., intrinsic activity, number of active sites, surface area, in-situ structure, etc. Nonetheless, complex interface-related hypotheses are postulated. Herein, we describe a pathway with essential electrocatalytic and analytical points that must be addressed before meaningful ab initio (mainly density functional theory, DFT) models and new hypotheses are raised. It comprises three parts: (i) determining if the activity changed intrinsically, (ii) revealing the in-situ composition, and (iii) identifying the active sites and the reaction mechanism. We anticipate that this perspective helps authors and reviewers acknowledge electrocatalysis' tremendous complexity and provides a systematic pathway to check if fundamental aspects are covered before complex, potentially misleading hypotheses are raised.