Black Phosphorous Mediates Surface Charge Redistribution of CoSe2 for Electrochemical H2O2 Production in Acidic Electrolytes

Abstract Electrochemical generation of hydrogen peroxide (H 2 O 2 ) by two‐electron oxygen reduction offers a green method to mitigate the current dependence on the energy‐intensive anthraquinone process, promising its on‐site applications. Unfortunately, in alkaline environments, H 2 O 2 is not stable and undergoes rapid decomposition. Making H 2 O 2 in acidic electrolytes can prevent its decomposition, but choices of active, stable, and selective electrocatalysts are significantly limited. Here, the selective and efficient two‐electron reduction of oxygen toward H 2 O 2 in acid by a composite catalyst that is composed of black phosphorus (BP) nailed chemically on the metallic cobalt diselenide (CoSe 2 ) surface is reported. It is found that this catalyst exhibits a 91% Faradic efficiency for H 2 O 2 product at an overpotential of 300 mV. Moreover, it can mediate oxygen to H 2 O 2 with a high production rate of ≈1530 mg L −1 h −1 cm −2 in a flow‐cell reactor. Spectroscopic and computational studies together uncover a BP‐induced surface charge redistribution in CoSe 2 , which leads to a favorable surface electronic structure that weakens the HOO* adsorption, thus enhancing the kinetics toward H 2 O 2 formation.