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

Abstract

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.

An efficient, green, and residual oxidant-free wastewater treatment technique enabled by coupling a dual-cathode heterogeneous electro-Fenton process and UV radiation in tandem

“…, sequential 2e − ORR and Fenton activation). 6 However, the catalytic cathode in the present work only exhibits activation function for H 2 O 2 , which allows high loading of FeOCl on GF to thoroughly stimulate the catalytic potential of the composite cathode. The brighter colors corresponding to Fe, O, and Cl elements compared to the C element in the energy dispersive spectroscopy (EDS) results strongly demonstrate the rather high FeOCl loading of the synthesized FeOCl/GF composite cathode (Fig.…”

“…As shown in Fig. 5e, HEF/UV probably represents the state-ofthe-art catalytic performance with corresponding k values 2.7 to 48.4-fold higher than other systems, 6,15,[36][37][38][39][40][41][42][43][44][45] suggesting the significant synergy between electro-and photo-catalysis. In view of the excellent performance of the HEF/UV tandem system, its feasibility for real industrial antibiotic wastewater treatment was evaluated.…”

“…8 In this context, heterogeneous EF (HEF) with solid-phase iron catalyst-functionalized carbonaceous cathode supports has recently been extensively developed and validated to effectively overcome these bottlenecks while bypassing the time-consuming and costly dispersion/separation procedures of catalyst particles in typical suspended heterogeneous processes. 4,6…”

Perspectives of Wood-Inspired Electro-Fenton Catalysis for Energy-Efficient Wastewater Decontamination

“…Recently, a chainmail catalysis technique has been utilized to address this issue by employing an electron penetration process through a coated carbon layer to encapsulate the metal catalyst, resulting in reduced metal corrosion and enhanced catalyst stability. For example, Cui et al successfully applied an electrochemical deposition method to coat the carbon-clothsupported iron oxychloride (FeOCl/CC) electrode surface with a thin layer of reduced graphene oxide (rGO), 96 resulting in high stability with minimal iron leaching (0.57%) while maintaining catalytic activity. Through analyzing the structure−activity relationship by theoretical calculations, electronpenetration-triggered H 2 O 2 activation on the outermost surface of rGO primarily contributed to the balanced activity and stability.…”

Selective Oxygen Activation to Reactive Oxygen Species on a Carbon Layer-Encapsulated CuxO Electrocatalyst for Water Purification

“…Several studies have confirmed that the electron penetration through a carbon layer from the inner active metallic oxide core to the outer carbon layer shell could stimulate efficient catalytic activity for activating O 2 to ROS on the carbon layer surface with oxygen-enriched functional groups (−COOH, C–O–C, etc. ). , Thus, if the Cu x O could be encapsulated in the carbon layer with oxygen-enriched functional groups, the obtained Cu x O@C core@shell structure composite photocathode was highly likely to achieve highly reactive, durable, and selective OA reaction.…”