Kirkendall Effect-Driven Interface Engineering Facilitates Water Dissociation for Dual-Site H2O2 Electrosynthesis Simultaneously at the Anode and Cathode

Abstract

The direct integration of renewable energy into H₂O₂ electrosynthesis systems offers a promising strategy to minimize energy losses and costs. Due to the intermittency of renewable energy, the dual-site catalysts must efficiently enable both the two-electron oxygen reduction reaction (2e⁻ ORR) and water oxidation reaction (2e⁻ WOR). The Kirkendall effect was employed to engineer interfaces and construct a NiZnO_x─C catalyst with exposed (100) facets. The hetero-cluster NiO_x induces oxygen vacancies and built-in electric fields, which facilitate water activation and subsequent formation of hydrogen and hydroxyl radicals, thereby enabling a single catalyst to rapidly electrosynthesize H₂O₂ at both the anode and cathode. Notably, 2e⁻ ORR on the cathode enabled rapid synthesis of high-concentration H₂O₂ (33987 mg L⁻¹, 33.18 mol g_catalyst⁻¹ h⁻¹). NiZnO_x─C achieves stable 2e⁻ ORR/WOR coupling in a continuous-flow reactor, operating reliably for 4 h under simulated alternating current (AC) and peaking at a total Faradaic efficiency of 150.9% under amperage-level direct currents. This work provides insights into interface engineering based on the Kirkendall effect, demonstrating the feasibility of directly integrating intermittent renewable energy into H₂O₂ electrosynthesis systems.