Electrochemical production of H2O2 on palladium-based clusters driven by metal–support interaction

Abstract

Utilizing palladium (Pd) clusters as active sites offers a promising route to minimize noble metal consumption in electrochemical hydrogen peroxide (H₂O₂) production. In this work, we present a synthesis approach for anchoring Pd-based clusters onto carbon-supported CeO₂ nanosubstrates to enable efficient H₂O₂ generation via the two-electron oxygen reduction reaction (ORR) pathway. By systematically adjusting Pd loading, we evaluated its impact on H₂O₂ yield and production rate. The catalyst with the lowest Pd content (0.027 wt%) exhibited outstanding performance, achieving 97% H₂O₂ selectivity, 94.2 faradaic efficiency at 0.7 V vs. RHE, and a peak production rate of 195.8 mol g_Pd⁻¹ h⁻¹. A formulation containing 0.35 wt% Pd delivered a peak ORR mass activity nearly three times as high as that of commercial 10 wt% Pd/C, while retaining comparable electrochemical stability. These enhancements are attributed to synergistic effects among isolated PdO clusters, CeO₂ nanocrystals, and the conductive carbon support, which together facilitate oxygen adsorption and promote the two-electron ORR pathway. Analysis after accelerated durability testing further revealed a tendency toward cluster agglomeration and mass transfer from smaller to larger nanocrystals, indicative of a coarsening mechanism. Overall, this study underscores the promise of low-Pd PdO–CeO₂–carbon hybrid catalysts for scalable and efficient H₂O₂ electrosynthesis, while highlighting stability as a critical area for future improvement.