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.