A critical review on cathode modification methods for efficient Electro-Fenton degradation of persistent organic pollutants

• Mechanisms of EF and fundamentals/necessity of cathode modification. • Current cathode modification methods with reported performances in removing POPs. • Pros/cons and perspectives of cathode modification for EF degradation of POPs. The Electro-Fenton (EF) technology has received significant research attention because of its efficacy in the degradation of persistent organic pollutants (POPs), which mainly relies on the in-situ generation of H 2 O 2 via the 2-electron oxygen reduction reaction and the subsequent formation of • OH. However, the practical application of the EF technology still needs to deal with shortcomings such as the limited performance of the traditional heterogeneous catalyst and the restricted generation of • OH that could be overcome by performing modification on the cathode. This work reviewed the reported cathode modification methods including thermal and (electro)chemical treatment and modification based on materials such as metals, graphene, carbon nanotubes, and polymers. Furthermore, the documented performances of the EF systems with differently modified cathodes in degrading specific POPs were presented. Finally, the advantages and limitations of these cathode modification methods were discussed, and some research perspectives were proposed to improve the practicability and feasibility of the EF technology.