Boundary-Rich Carbon-Based Electrocatalysts with Manganese(II)-Coordinated Active Environment for Selective Synthesis of Hydrogen Peroxide.

Coordinated manganese (Mn) electrocatalysts owing to their electronic structure flexibility, non-toxic and earth abundant features are promising for electrocatalytic reactions. However, achieving selective hydrogen peroxide (H 2 O 2 ) production through two electron oxygen reduction (2e-ORR) is a challenge on Mn-centered catalysts. Targeting this goal, we report on the creation of a secondary Mn(II)-coordinated active environment with reactant enrichment effect on boundary-rich porous carbon-based electrocatalysts, which facilitates the selective and rapid synthesis of H 2 O 2 through 2e-ORR. The catalysts exhibit nearly 100 % Faradaic efficiency and H 2 O 2 productivity up to 15.1 mol g cat -1  h -1 at 0.1 V versus reversible hydrogen electrode, representing the record high activity for Mn-based electrocatalyst in H 2 O 2 electrosynthesis. Mechanistic studies reveal that the epoxide and hydroxyl groups surrounding Mn(II) centers improve spin state by modifying electronic properties and charge transfer, thus tailoring the adsorption strength of *OOH intermediate. Multiscale simulations reveal that the high-curvature boundaries facilitate oxygen (O 2 ) adsorption and result in local O 2 enrichment due to the enhanced interaction between carbon surface and O 2 . These merits together ensure the efficient formation of H 2 O 2 with high local concentration, which can directly boost the tandem reaction of hydrolysis of benzonitrile to benzamide with nearly 100 % conversion rate and exclusive benzamide selectivity.