MoO x as an Oxidized Incorporation Modulates Nickel Sites for Efficient H2O2 Electrosynthesis at 200 mA cm–2

Abstract Electrochemical H2O2 synthesis via the two-electron oxygen reduction reaction (2e– ORR) enables on-site production, yet its practical application is hindered by the scarcity of catalysts that can simultaneously deliver high selectivity, activity, and stability at industrial current densities. Here, we report molybdenum incorporation into nickel oxide, where Mo is predominantly present as atomically dispersed, oxygen-coordinated Mo species (denoted as MoOx). The resulting MoOx–NiO catalyst features a hybrid crystalline–amorphous structure. Spectroscopy and density functional theory calculations reveal that MoOx induces a localized electron redistribution, generating electron-rich Ni sites with a formal valence below + 2 (Ni2–x) adjacent to MoOx as key active sites. These Ni2–x sites tune the adsorption free energy of the critical OOH intermediate and favor the 2e– pathway over the competing 4e– pathway. The MoOx–NiO achieves >95% H2O2 selectivity over a potential range of 0.25–0.70 V vs RHE and a high production rate of 34.8 ± 0.8 mol gcat–1 h–1 at an industrial current density of 200 mA cm–2 in a flow cell, together with high Faradic efficiency and long-term operational stability. These findings show that engineering the chemical state and oxygen coordination of a dopant can modulate the local electronic structures of host metal sites and thereby influence catalytic pathways, providing a strategy for the design of advanced oxide electrocatalysts.