Dynamic Evolution of Zeolite Framework and Metal-Zeolite Interface

Zeolites and metal-zeolites are a class of porous materials that have been widely utilized in industry. So far, several fundamental questions relating to the dynamic evolution of the zeolite framework and the metal-zeolite interface remain unanswered. Contrary to the classical view of zeolites as a static, rigid, and changeless material, the framework atoms and foreign metals in zeolites can dynamically interconvert under the pretreatment or reaction conditions, making it difficult to identify the real active centers and mechanisms. With the development of characterization techniques and theoretical calculations, a more profound understanding of the dynamic evolution of zeolite framework and metal-zeolite interface at the atomic scale has been achieved. This critical Review will feature the recent progress of the dynamic evolution of zeolite and metal-zeolites, mainly focusing on the T-O-T bonds breaking and formation, metal valence state transformation, phase evolution, and migration. We compare these proposed mechanisms and analyze their suitability in distinct experimental conditions. We highlight that the identification of the active sites and catalytic mechanism of zeolites and metal-zeolites should be cautious and should consider the dynamic evolution of the active centers under reaction conditions. Finally, we summarize the usages and limitations of different characteristic techniques, propose some future research directions about the dynamic evolution of zeolites and metal-zeolites, and hope to bridge the gaps between the knowledge achieved in characterizations and the real nature of the active sites to guide zeolite-based materials synthesis, modification, and application.