Platinum-group metals have an irreplaceable role in electro-catalyzing oxygen reduction reaction (ORR) process due to the affinity of oxygen and oxygenated intermediate. However, large overpotential and poor long-term durability prohibit their utilization in the scalable industrial application. Owing to their inherent scarcity, substantial improvements in the electrocatalytic performance (both selectivity and stability) of the catalysts are urgently necessary. Herein, a synergistic hybrid PtPd-Al₂O₃ catalyst is developed for high-selective and long-term stable hydrogen peroxide (H₂O₂) electroproduction. Synchrotron radiation characterizations are carried to clarify the synergistic effect in the catalyst. The incorporation of Pd with Pt induces a valence band restructuring and reconstructs the coordination environment of the nanoparticles. For H₂O₂ electrosynthesis through the 2e^- ORR, these electronic and structural modifications resulted in optimal adsorption energies of reaction intermediates. Therefore, the synergy hybrid of Pt and Pd not only enhance electrocatalytic activity and selectivity (96%) but also create a new coordination structure in the catalyst, increasing its long-term durability. This study introduces a new paradigm for the development of high-performance H₂O₂ electrocatalyst by demonstrating the synergistic dual function of Pd as electron promoter and structure stabilizer.