Tianjin University Develops a Superhydrophobic Air-Breathing Cathode for Efficient Hydrogen Peroxide Generation

An article entitled Superhydrophobic Air-Breathing Cathode for Efficient Hydrogen Peroxide Generation through Two-Electron Pathway Oxygen Reduction Reaction was published in ACS Applied Materials & Interfaces. It is conducted by associate professor Nan Li from the School of Environmental Science and Engineering.

In this research, PTFE_0.57showed the highest H₂O₂ yield of 3005 ± 58 mg L⁻¹h⁻¹(at 25 mA cm⁻²) and highest current efficiency (CE) of 84% (at 20 mA cm⁻²).It is achieved via tuning catalyst mesostructure and hydrophilicity/hydrophobicity by adjusting polytetrafluoroethylene (PTFE) content in graphite/carbon black/PTFE hybrid catalyst layer (CL).Rotating ring disk electrode (RRDE) results demonstrated that less PTFE content in CLs results in less electrons transferred and better selectivity toward two-electron ORR.

It is proved that the H₂O₂ decomposition reaction was the major side reaction. Higher PTFE content increased the hydrophilicity of CL for excessive H⁺ and insufficient O₂ diffusion, which induced H₂O₂ decomposition into H₂O. Simultaneously, the electroactive surface area of CLs decreased with higher PTFE content, from 0.0041 m²g⁻¹ of PTFE_0.57 to 0.0019 m²g⁻¹ of PTFE_4.56. The major catalytic active sites for two-electron ORR were 3−10 nm mesopores. Besides, higher PTFE content in CL leads to the increase of total impedance (from 14.5 Ω of PTFE_0.57 to 18.3 Ω of PTFE_4.56), which further hinders the electron transfer and ORR activity.

By Nan Li from the School of Environmental Science and Engineering

Editor: Eva Yin