Atomic Size Misfit for Electrocatalytic Small Molecule Activation

Abstract The efficient activation of small molecules such as H 2 O, CO 2 , and N 2 for sustainable fuel and chemical production is a critical challenge in catalysis, owing to the strong covalent bonds (O─H, C═O, N≡N) that resist easy cleavage. Catalysts are pivotal in overcoming these energy barriers, enhancing reaction rates and selectivity. The strategy of atomic size misfit, which introduces structural defects like vacancies, grain boundaries, and dislocations, has gained attention as a promising approach to optimize catalytic activity. This strategy modulates atomic interactions, alters electronic structures, and enhances the reactivity of active sites, facilitating the activation of small molecules. Moreover, this approach holds significant potential for reducing environmental impact by enabling more efficient and sustainable chemical processes. However, current research on atomic size misfit remains fragmented, lacking a unified framework. A comprehensive review of this strategy is essential to consolidate its mechanisms, applications, and integration with other catalytic tuning methods such as alloying and doping. This review aims to provide valuable insights into the design of next‐generation catalysts, guiding future developments in energy conversion technologies and offering pathways for practical, scalable applications in small molecule activation.