The advantages of ammonia as a hydrogen carrier have led to proposals for on-site hydrogen production through its decomposition. Rapid cold start of ammonia decomposition is crucial for applications such as ammonia-powered vehicles, but conventional heating methods are challenged by the high decomposition temperature of ammonia. In this study, we successfully achieved the rapid cold start of ammonia decomposition using Co nanoparticle catalysts driven by magnetic induction heating, demonstrating excellent catalytic performance and stability. The magnetic induction heating-driven ammonia decomposition system was integrated with a hydrogen fuel cell, proving its ability to achieve the cold start of ammonia decomposition within 10 s, as demonstrated by comparative experiments using 75% H2-25% N2 from a gas cylinder as the control. This study provides a deeper understanding of hysteresis heating catalysis, promoting the practical use of ammonia as a hydrogen carrier for rapid hydrogen production in the energy industry.