Understanding the dynamic behavior of catalysts under realistic reaction conditions is essential for the rational design of nanomaterials with improved performance and stability. In situ and operando synchrotron-based techniques, provide powerful tools to monitor structural transformations, electronic states, and metal-support interactions in real time. These insights bridge the gap between structure and function, enabling the optimization of active sites and the development of more efficient and durable catalytic systems. Case studies highlight how such advanced characterization approaches guide the design of metal oxide-based catalysts for sustainable energy conversion applications.