Enhanced reactive oxygen species via in situ producing H2O2 and synchronous catalytic conversion at stable modified copper foam cathode for efficient high-concentration organic wastewater treatment and simultaneous electricity generation

Efficient high-concentration organics degradation (including 2-CP, phenol, and tetracycline) and simultaneous electricity generation were achieved via in situ producing H2O2 and synchronous catalytic conversion to more reactive oxygen species at stable modified copper foam cathode. The cathode was synthesized using the one-pot electrodeposition method and was used to in-situ generate H2O2 through the two-electron reduction of oxygen. The produced H2O2 was then catalytically converted into ·OH and ·O2− simultaneously. The results showed that the system using the Au–Fe co-modified cathode achieved an optimal rhodamine b (50 mg L−1) removal ratio and the removal ratios of 2-CP, phenol and tetracycline were all higher than 90% in 120 min. Meanwhile, it exhibited a high conversion performance of organics into electricity, which is superior to most of the reported PFC (Photocatalytic Fuel Cell) systems. Electron spin resonance test was conducted to ascertain the role of ·O2− and ·OH in the organics degradation. Furthermore, the Au–Fe-modified cathode exhibited superior stability for long-term application in the pH range of 3–7, which can be attributed to the protection of photocurrent and the interaction between Cu and Fe.