Surface Acidity Engineering: From Fundamental Insights to Universal Design Rules for Electrocatalytically and Electrically Active Oxides

ABSTRACT Surface acidity, initially introduced as a sensitive descriptor for predicting the oxygen exchange rate at solid oxide surfaces, has rapidly evolved into a versatile design strategy that provides unified guidance for enhancing catalytic performance across a wide range of oxide systems. This broad utility arises from its ability to markedly modulate the concentration of charged species at the surface, leading to corresponding variations in the surface activity of functional oxides. Beyond performance modulation, this review highlights recent advances in the use of surface acidity engineering for reactivation of degraded electrodes and extended catalyst life, as well as its role in promoting structural reconstruction for interfacial stabilization. We also provide a comprehensive discussion of the mechanistic origins of surface acidity engineering, describing in turn responses governed by variations induced in surface space charge properties, the reconfiguration of surface potential, and diverse complementary viewpoints. Finally, by emphasizing the conceptual simplicity and broad tunability of this strategy, the review concludes by outlining future research directions and practical perspectives for implementing acidity‐based design principles in diverse applications, including energy conversion, energy storage, functional electronics, and beyond‐conventional electrochemical systems.