Bifunctional Catalytic Cooperativity on Nanoedge: Oriented Ce-Fe Bimetallic Fenton Electrocatalysts for Organic Pollutant Control

Abstract

Electro-Fenton (EF) is one of the promising clean and renewable technologies for organic pollutant control. However, insufficient hydrogen peroxide (H2O2) generation and the subsequent hydroxyl radicals (•OH) conversion still prevent the wide applications of EF. Herein, we report a Ce-doped vertically aligned α-FeOOH nanoflakes anchored on a carbon felt (CF) cathode for EF operation. In this system, a high concentration H2O2 (113.6 mg/L on 4 cm2 cathode) is generated in 60 min, and being efficiently catalyzed to •OH by virtue of the active nanoedge (1.6 nm thickness) of Ce-doped α-FeOOH. The •OH production rate is calculated as high as 4.2 mM/W/cm2/min, which is ∼6.6-fold higher compared with the unmodified CF electrode. Moreover, this novel cathode achieves a complete removal (100% removal rate) of ultrahigh concentration chloramphenicol (1.1 mM, 355 mg/L) in 8 h and a high mineralization rate (94%) in 29 h in a scaled-up EF system. Density functional theory calculations (DFT) reveal that the Ce doping in α-FeOOH greatly promotes the conversion of H2O2 into •OH. This study not only offers a novel cathode structure for EF process but also opens radically new prospects for applied environmental catalysis.