To meet the rapid response requirements of distributed energy supply systems for dynamic hydrogen production rates, a Ru/Ce-Al catalyst was prepared using a precipitation-hydrothermal method. This method addresses the challenge of maintaining dynamic stability in ammonia-decomposition-induced hydrogen production units under variable load conditions. Characterization techniques, such as XRD, NH₃-TPD, and H₂-TPR, were used to reveal the systematic regulation mechanism by which Al³⁺ doping in CeO₂ and the Ce/Al stoichiometric ratio influence the evolution of oxygen vacancies in the support; in addition, their ammonia-decomposition-induced hydrogen production performance were investigated. The results show that Al³⁺ doping induces the formation of a Ce-Al-O solid solution, which optimizes the distribution of oxygen vacancies on the support surface through strong metal-support interactions (SMSIs), thereby enhancing the dispersion of active metal Ru. At a space velocity of 15 000 h^-1 and reaction temperature of 525 ℃, the Ru/3Ce-Al catalyst achieved an ammonia-conversion efficiency of 93%. Its balanced performance over a wide temperature range (500 ℃ -550 ℃) effectively excessive minimized reaction rates at high temperatures that could lead to catalyst sintering. After 100 h of operation, the catalyst maintained an ammonia-conversion efficiency of 91.8%. An ammonia-hydrogen fuel-cell-based energy supply system, constructed using this catalyst, exhibited power, voltage, and current fluctuations of only 2.3%, 1.1%, and 0.6%, respectively, under a 2 kW load. Furthermore, in step-load tests (0.22 kW→0.45 kW→0.22 kW), the system demonstrated rapid power and current responses with pressure fluctuations below 5‰. This result verified its dynamic response capability and operational stability in complex environments.