Enhanced Oxygen Diffusion and Catalytic Performance of Self-Breathing CB/CNT Cathodes for High-Efficiency H2O2 Production (in Dual-Chamber Reactors)

A novel self-breathing gas diffusion electrode was developed by loading carbon nanotubes (CNTs) and carbon black (CB) onto the surface of graphite felt through vacuum filtration. This electrode features a well-structured mesoporous network and a stable three-phase interface, which enable efficient oxygen mass transfer and enhance the self-breathing capability. The incorporation of carbon nanotubes and carbon black significantly boosts the electrode's catalytic performance. In a dual-chamber reactor operating at a current density of 12 mA/cm 2 and an initial pH of 3, the system achieved an H 2 O 2 concentration of 4,691 mg/L within 1 hour, with an energy consumption of 6.58 kWh/kg H 2 O 2 substantially outperforming conventional gas diffusion electrodes. The dynamic pH regulation in the dual-chamber system optimizes the 2e - ORR pathway, leading to corresponding changes in proton transfer pathways and adsorbed species within the Helmholtz plane. Additionally, the presence of reactive hydrogen (H*) enhances the chemisorption of O 2 and facilitates its hydrogenation to form the *OOH intermediate. The electrode exhibited excellent stability, maintaining H 2 O 2 yields above 4000 mg/L over 5 cycles and nearly complete degradation of the simulated contaminants within 30 min in an electro-Fenton system application. These results highlight the electrode's potential for efficient H 2 O 2 synthesis and environmental remediation.