Mechanism investigation of enhanced electrochemical H₂O₂ production performance on oxygen-rich hollow porous carbon spheres

Electrochemical oxygen reduction is a promising approach for the sustainable decentralized production of H₂O₂, but its viable commercialization is hindered by the insufficient development of efficient electrocatalysts. Here, we demonstrate a promising carbon-based catalyst, consisting of oxygen-rich hollow mesoporous carbon spheres (HMCSs), for selective oxygen reduction to H₂O₂. The as-prepared HMCS exhibits high onset potential (0.82 V) and half-wave potential (0.76 V), delivering a significant positive shift compared with its oxygen-scarce counterparts and commercial Vulcan carbon. Moreover, excellent H₂O₂ selectivity (above 95%) and electrochemical stability (7% attenuation after 10 h operation) make this material a state-of-the-art catalyst for electrochemical H₂O₂ production. The outstanding performance arises from a combination of several aspects, such as porous structure-facilitation of mass transport, large surface area, and proper distribution of oxygen-containing functional groups modification on the surface. Furthermore, the proposed oxygen reduction reaction (ORR) mechanism on HMCS surface reveals that –OH functional groups help promote the first electron transfer process while other oxygen modification facilitate the second electron transfer.