Doping Stabilizing Isolated Active Sites in Perovskite Lattice for Stable H₂O₂ Electroproduction

Developing the efficient catalysts with both high 2e^- selectivity and stability remains challenging for on-site hydrogen peroxide (H₂O₂) synthesis. Perovskite oxides possess dense isolated active sites to convert O₂ into H₂O₂, yet their intrinsic structural instability is also equally noteworthy. In this work, one kind of silver-based perovskites, AgNbO₃, and the structure stabilization approach are proposed for H₂O₂ electrosynthesis. The Ag exsolution from the perovskite phase, which triggers the metallic Ag assemblies on surface, is identified as a key origin of electrochemical destabilization for the 2e^- ORR process. Simultaneously, the Zr-doping-induced stabilization approach is put forward. The introduction of high-oxyphilic Zr⁴⁺ leads charge delocalization of oxygen in the [NbO₆] octahedra toward Ag-site region, thereby enhancing Ag-O covalency as evidenced by the increased integrated crystal orbital Hamilton population values and the suppressed exsolution thermodynamics, while the sharply declined phase-transition constant reconfirms that the Zr incorporation retards the Ag-migration kinetics in terms of experimentation. The resulting Zr-doped AgNbO₃ shows outstanding structural stability maintaining the above 90% Faradaic efficiency even at high-current and long-term operation. This work unveils the origination of perovskite destabilization during the 2e^- ORR process, and offers a general strategy for stabilizing isolated active sites in electrochemical application.