Cost-effective electrogeneration of H₂O₂ utilizing HNO₃ modified graphite/polytetrafluoroethylene cathode with...

Electrochemical 2-electrons oxygen reduction process has been regarded as the effective strategy for H₂O₂ generation in wastewater treatment. However, its large-scale application is still limited by the relatively high cost of the carbon materials and short-term stability. In this study, a nitric acid modified graphite/polytetrafluoroethylene (PTFE) composite cathode with exterior hydrophobic film was fabricated for cost-effective electrogeneration of hydrogen peroxide (H₂O₂). Experimental results show that 2 M HNO₃ modification rendered the introduction of much more defect sites and oxygen/nitrogen-containing groups on graphite. As a result, H₂O₂ electrogeneration was 3.0 times as much as that of virgin graphite counterpart at 3 mA cm^-2. Moreover, the additional introduction of exterior hydrophobic film on the as-prepared graphite/PTFE cathode did not only further promote H₂O₂ electrogeneration, but also endowed the cathode with strong hydrophobic stability. As for the modified cathode with exterior hydrophobic film, the influence of mass graphite/PTFE binder ratio (1:1-4:1) and pH (3.0-9.0) on H₂O₂ electrogeneration was slight, but the current density (3.0-15 mA cm^-2) had evident effect on H₂O₂ electrogeneration. Generally, owing to its low price and being easily available, the modified graphite would be cost-effectively utilized to prepare the gas diffusion cathode for the large-scale electrogeneration of H₂O₂ in industry.