Regulating the bubble-water/catalyst interface microenvironment for accelerated electrosynthesis of H2O2via optimizing oxygen functional groups on carbon black†

Abstract

The selective electrosynthesis of hydrogen peroxide (H₂O₂) via the oxygen reduction reaction (ORR) holds significant promise for sustainable chemical production. In this study, we optimized the oxygen functional groups on carbon black (CB) to modulate the bubble-water/catalyst interface microenvironment, thereby enhancing the electrosynthesis of H₂O₂. A simple hydrothermal method was employed to functionalize the carbon black surface, and the oxygen content was systematically adjusted by varying the temperature and time. The electrochemical performance of the resulting catalysts was evaluated, with CB-85-6 h demonstrating the highest H₂O₂ productivity (3302.23 mmol g_cat⁻¹ h⁻¹) and selectivity (90.1%). EDS, XPS, Raman spectroscopy, and contact angle analysis demonstrated that the introduction of oxygen functional groups enhanced the surface hydrophobicity, facilitating the adsorption and activation of oxygen. Density functional theory (DFT) calculations further confirmed that the COOH at the edge of graphene, C–O–C at the basal 2 and CO at the edge optimize the binding energy of the reaction intermediates, improving both the selectivity and efficiency of H₂O₂ production. This work provides valuable insights into the design of highly efficient catalysts for electrocatalytic H₂O₂ synthesis.