Electrochemical Synthesis of Hydrogen Peroxide Enabled by Tri-Coordinated Cobalt Sites in Silicate-1 Zeolite

Electrochemical synthesis of hydrogen peroxide (H₂O₂) via metal-catalyzed two-electron oxygen reduction reaction (2e^- ORR) emerges as a sustainable alternative to the traditional anthraquinone method. However, metal catalysts are commonly supported by graphitic carbon that is susceptible to being oxidized by reactive oxygen species generated in ORR and have limited oxygen capacities. Here, we report a silica-based electrocatalyst embedding cobalt (Co) sites into silicate-1 (S-1) zeolite, which exhibited exceptional 2e^- ORR performance. The aligned microporosity of S-1 zeolite highly isolated Co sites to derive a specific tri-coordination unit of Co(OSi)₃ moiety. The nanochannels of S-1 zeolite further provide robust and substantial reaction spaces, where the Co(OSi)₃ moiety facilitates O₂ chemisorption and holds moderate bonding with *OOH intermediates to reduce the barrier of H₂O₂ formation. It achieved high Faradaic efficiency over 96% and a steady yield of 11.56 mol g_cat ^-1 h^-1 in a gas diffusion electrode setup. This work provides a novel insight into 2e^- ORR on Co sites and highlights the potential of zeolite-based materials for electrochemical applications.