Enhanced electro-Fenton catalytic performance with in-situ grown Ce/Fe@NPC-GF as self-standing cathode: Fabrication, influence factors and mechanism

Heterogeneous electro-Fenton (E-F) is considered as an attractive technique for efficient removal of refractory organic pollutants in wastewater. The regeneration of FeII and catalyst reusability are key issues for effective and sustainable degradation. Developing binder-free iron phase/carbon composite cathode is a feasible strategy. In this work, the stable Ce/Fe-nanoporous carbon modified graphite felt electrode (Ce/Fe@NPC-GF) was fabricated using in situ solvothermal method and subsequent carbonization treatment, which worked as the cathode in a heterogeneous electro-Fenton system to degrade sulfamethoxazole. The electrocatalytic activity was significantly improved with doping of Ce. It was found that mesoporous Ce/Fe@NPC-GF cathode demonstrated high oxygen reduction activity and low resistance. The co-existence of Fe-II/Fe-III and Ce-III/Ce-IV redox couples enhanced remarkably interfacial electron transfer, promoting in-situ H2O2 generation and decomposition, sequentially boosting the production of reactive radicals ((OH)-O-center dot and O-center dot(2)-). Under 20 mA and pH 3, Sulfamethoxazole (SMX) was basically degraded in 120 min, and the removal rate was satisfactory in wide pH (2-6). After 8 cycles, the electrode could still maintain high stability and outstanding catalytic capacity. This work displayed a novel in-situ preparation method of composite cathode with excellent catalytic performance in E-F system, which offered inspiration for developing efficient heterogeneous electro-Fenton cathode material. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrated the efficient removal of sulfamethoxazole using Ce/Fe-nanoporous carbon modified graphite felt electrode in a heterogeneous electro-Fenton system, highlighting the enhanced electrocatalytic activity with Ce doping. The mesoporous Ce/Fe@NPC-GF cathode showed high oxygen reduction activity, low resistance, and remarkable interfacial electron transfer, leading to in-situ H2O2 generation and production of reactive radicals. The electrode exhibited high stability and outstanding catalytic capacity even after 8 cycles, emphasizing its potential as an efficient heterogeneous electro-Fenton cathode material.