Enhancing H2O2 production with a self-breathing gas diffusion electrode fabricated via ultrasonic impregnation and vacuum filtration

•The electro-catalytic activity of the cathode towards 2e− ORR is enhanced.•A gas–liquid-solid tri-phase interface is established.•Oxygen for 2e− ORR process is obtained through the spontaneous adsorption of O2.•The self-breathing cathode demonstrates a substantial H2O2 yield.•Hydrophobic layers are established on the surface and within the cathode. In this study, an electro-Fenton gas diffusion electrode featuring air self-respiration was fabricated by incorporating carbon nanotubes, carbon nitride, and polytetrafluoroethylene onto graphite felt. The fabrication process involved a synergistic approach of ultrasonic impregnation and vacuum filtration, establishing a gas–liquid-solid tri-phase interface both on the surface and within the electrode. This preparation method facilitates autonomous air intake, diffusing it to the tri-phase reaction interface, thereby eliminating the necessity for aeration and reducing operational costs. The optimal electrode preparation conditions were determined through Box-Behnken Design response surface experiments, leading to the enhancement of H2O2 production conditions. Under the optimized conditions, H2O2 accumulation reached 45.83 mg L−1 cm−2h−1, surpassing the performance achieved with conventional ultrasonic impregnation and vacuum filtration methods. Furthermore, the performance of self-breathing and the impact factors are explored. Finally, the electrode’s efficacy was demonstrated through the degradation of phenol and bisphenol A with concentrations of 100 mg L−1 exhibiting degradation rates of 92 % and 95 %, respectively, within 60 min.