The article delves into the intricate mechanism of carbon methanation in zirconium-cobalt alloys, crucial for large-scale hydrogen isotope gas storage. Despite the vital role of these alloys in hydrogen storage, the formation of methane from carbon impurities during the hydrogen storage cycle has been relatively understudied. By analyzing gas compositions released during hydrogen reactions at different temperatures, researchers observed a temperature-dependent increase in methane production. They identified a macroscopic carbon migration process influenced by lattice reorganization, elucidating the crucial role of crystal structure in methane formation. Combining experimental and computational approaches, the study identified a pathway for methanation on the crystal surface, highlighting the efficiency of zirconium-cobalt alloys as catalysts. The push towards clean energy and the demand for efficient hydrogen storage materials in fusion reactors emphasize the significance of understanding and optimizing materials like ZrCo alloys. The findings not only advance the knowledge on methane generation in hydrogen storage but also provide insights into enhancing material properties and system stability for future energy applications.