Overcoming the Activity–Stability Trade-Off in Heterogeneous Electro-Fenton Catalysis: Encapsulating Carbon Cloth-Supported Iron Oxychloride within Graphitic Layers

Maintaining a long-term service life of catalytic materials under the established configuration and design concept is a key focus in catalytic process research and development, especially for iron-functionalized cathode-based heterogeneous electro-Fenton (EF) processes operated under harsh conditions. Herein, a versatile and robust encapsulation engineering strategy is proposed based on the concept of tightly covering the surface of conventional iron-functionalized cathodes with an ultrathin carbon layer to significantly improve the stability of composite cathodes without causing activity loss. Taking carbon cloth-supported iron oxychloride (FeOCl/CC) as a model cathode catalyst, it was successfully encapsulated in a reduced graphene oxide protective shell (FeOCl/CC@rGO) using an electrophoretic deposition method, thereby achieving high stability due to negligible iron leaching (only 0.57% of FeOCl/CC), while maintaining almost unaffected activity due to electron penetration effect. Experimental analysis of the structure–activity relationship and theoretical calculations were used to establish the underlying molecular mechanism of electron penetration-triggered H2O2 activation on the outermost surface of rGO. This study uses an effective approach to overcome the activity–stability trade-off of integrated cathodes in heterogeneous EF processes, providing theoretical guidance for the rational design of high-performance cathodes with an encapsulated structure.