Boosted electrosynthesis of hydrogen peroxide on isolated metal sites through second-shell modulation

The electrosynthesis of hydrogen peroxide is limited by the competitive four-electron oxygen reduction reaction (ORR) pathway. The modulation for the adsorption of OOH* intermediate on active sites is considered as the effective approach to tune the ORR selectivity, but it remains challenging. Herein, we report the neighboring phosphorus atom in the second coordination shell to regulate the electronic structure of the isolated Ni-N₄ sites, leading to the favored OOH* adsorption and thus boosting the electrocatalytic ORR to hydrogen peroxide through the two-electron pathway. Spectroscopy characterizations and density functional theory calculations indicate the neighboring phosphorus atom in the second coordination shell triggers the electron transfer to central Ni atom, strengthening the adsorption of OOH* on Ni sites and thus increasing the catalytic performance for two-electron ORR, delivering a selectivity above 90% for production of hydrogen peroxide under the current density of 150 mA·cm⁻². This work reveals tailoring second coordination shell of isolated metal sites could be as a precise and efficient way to engineer the catalytic performance, which thus provides a promising approach to the design of advanced catalysts.