Metal-free electro-Fenton degradation of perfluorooctanoic acid with efficient ordered mesoporous carbon catalyst

Heterogeneous electro-Fenton with in situ generated H2O2 and •OH is a cost-effective method for the degradation of refractory organic pollutants, in which the catalyst is an important factor affecting its degradation performance. Metal-free catalysts can avoid the potential risk of metal dissolution. However, it remains great challenge to develop efficient metal-free catalyst for electro-Fenton. Herein, ordered mesoporous carbon (OMC) was designed as a bifunctional catalyst for efficient H2O2 and •OH generation in electro-Fenton. The electro-Fenton system showed fast perfluorooctanoic acid (PFOA) degradation with kinetics constant of 1.26 h-1 and high total organic carbon (TOC) removal efficiency of 84.0 % after 3 h reaction. The •OH was the main species responsible for PFOA degradation. Its generation was promoted by the abundant oxygen functional groups such as C-O-C and the nano-confinement effect of mesoporous channels on OMCs. This study indicated that OMC is an efficient catalyst for metal-free electro-Fenton system.