Highly efficient heterogeneous electro-Fenton degradation of organic pollutants using a FeNi-OH/NF cathode

Abstract

The electro-Fenton (EF) technology provided a promising way to degrade organic pollutants by in-situ producing H2O2 and decomposing it into hydroxyl radicals (OH). However, the degradation rate is restricted by the two-electron oxygen reduction reaction (ORR) rate of H2O2 generation and the production efficiency of OH, and the efficient EF cathode is important. Herein, we designed an efficient heterogeneous EF system with a Fe-doped β-Ni(OH)2 nanosheets/nickel foam (FeNi-OH/NF) cathode for phenol removal in water. FeNi-OH enhanced the electrochemically active area for H2O2 production and produced OH for pollutant degradation. The FeNi-OH/NF cathode demonstrates excellent heterogeneous EF catalytic activity with a degradation efficiency of phenol (99.4%) and total organic carbon (67.4%) in 2 h. The experiments and density functional theory (DFT) calculations further confirmed that the Fe-doped β-Ni(OH)2 on the nickel foam enhanced H2O2 adsorption and accelerated Fe3+/Fe2+ circulation, promoting the reaction of H2O2 with Fe2+ to produce OH for phenol degradation. This study provides a novel and efficient heterogeneous EF cathode for accelerating pollutant degradation securely and quickly.