Resolving Dynamic Behavior of Electrocatalysts via Advances of Operando X-Ray Absorption Spectroscopies: Potential Artifacts and Practical Guidelines.

Abstract

Although numerous techniques are developed to enable real-time understanding of dynamic interactions at the solid-liquid interface during electrochemical reactions, further progress in the development of these methods over the last several decades has faced challenges. With the rapid development of high-brilliance synchrotron sources, operando X-ray spectroscopies have become increasingly popular for revealing interfacial features and catalytic mechanisms in electrocatalysis. Nevertheless, the resulting spectra are highly sensitive to factors such as X-ray radiation, reaction environment, and acquisition procedures, all of which may potentially introduce artifacts that are often overlooked, leading to misinterpretations of electrocatalytic behaviors. In this perspective, several emerging hard X-ray spectroscopies used in electrocatalysis research are reviewed, highlighting their electronic transition processes, detection modes, and functional complementarity. Significantly, based on a case study of operando X-ray absorption spectroscopy at various beamlines, potential artifacts generated by X-ray irradiation are systematically investigated through photon-flux density-, dose-, and time-dependent studies of typical copper electrocatalysts. Accordingly, a practical protocol for conducting reliable X-ray spectroscopic measurements in operando electrocatalytic studies to minimize potential artifacts that can affect the resulting X-ray spectra, thereby ensuring accurate interpretation and a deeper understanding of interfacial interactions and electrocatalytic mechanisms, is established.