Electron transfer route tuning caused by photo-irradiation: Stability enhancement of N-doped carbon materials in Fenton-like reactions

Improving the stability of N-doped carbon materials is still a great challenge in Fenton-like reactions. Herein, a hollow structure with TiO2 nanoparticles supported on the inner surface of N-doped carbon spheres (H-TiO2 @NC) is designed for peroxydisulfate (PDS)-based Fenton-like reactions with photo-irradiation. Impressively, the stability of H-TiO2 @NC is greatly enhanced with photo-irradiation. The degradation rate constant of bisphenol A (BPA) with photo-irradiation is similar to 61 times larger than dark condition after four runs. The photovoltage enables more electrons to be transferred from BPA to PDS via active carbons. Less electrons from the carbon framework are expended, thus inhibiting the oxidation and deactivation of H-TiO2 @NC effectively. Additionally, the direct electron transfer (DET) process is improved due to conductivity enhancement, which also weakens the oxidation of carbon skeleton. This work provides a reliable method to enhance the stability of N-doped carbon materials. And giving some new insights into the mechanism of stability enhancement.