Selective removal of organic pollutants by advanced oxidation methods has been receiving increasing attention for environmental remediation. In this study, a novel catalyst, which can selectively oxidize phenolic compounds (PCs) based on their hydrophobicity, composed of metal–organic-framework-derived Fe/Fe3O4 and three-dimensional reduced graphene oxide (rGOF) is designed for peroxydisulfate (PDS) activation. This heterogeneous PDS activation system can completely degrade hydrophobic PCs within 30 min. By investigating the hydrophobic properties of eight representative PCs, a positive correlation between the hydrophobicity of PC and the reaction kinetics is reported for the first time. The selective removal stems from the strong interaction between highly hydrophobic PCs and the catalyst. Moreover, the mechanism investigation shows that the degradation reaction is triggered by interface reactive oxygen species (ROS). Our study reveals that the selective degradation of organic pollutants by PDS activation depends on the hydrophilic and hydrophobic properties of the pollutant and catalyst. The reported results provide new insights into a highly selective and efficient PDS activation system for organic pollutant removal.

Smart combining of electrooxidation of organic pollutant and electrocatalytic hydrogen evolution in a single reaction system is a promising solution for simultaneous wastewater treatment and renewable energy generation. Herein, we report a bifunctional electrolyzer with NiMoO 4 and its reduced derivative as the anode and the cathode for the phenol oxidation reaction (POR) and the hydrogen evolution reaction (HER), respectively. The anode shows high efficiency in phenol degradation, in which the direct oxidation by • OH on the anode surface is responsible for the POR. The cathode exhibits prominent HER performance with 67 mV overpotential at 10 mA/cm 2 and strong resistance to the poison effect from phenol degradation intermediates. It is demonstrated that the NiMoO 4based catalysts can be readily used as highly efficient and robust electrodes for simultaneous phenol degradation and H 2 generation. Such a bifunctional electrolyzation system opens a new avenue of advanced technologies for wastewater treatment and renewable energy production.

We report an electrolysis system using NiFe layered double hydroxide/CoMoO 4 /nickel foam (NFLDH/CMO/NF) as the anode and CMO/NF as the cathode for simultaneous phenol electro-oxidation and water electrolysis. This system shows high performance for both phenol degradation and hydrogen evolution. We demonstrate that the degradation rate of phenol on the active anode is governed by the mass transfer rate at a low phenol concentration (0.5−2 mM) and by the electro-oxidation rate at a high phenol concentration (5 mM). The anodic oxygen evolution reaction (OER) can promote the phenol degradation through enhanced mass transfer efficiency. More importantly, the common deactivation issue of phenol electro-oxidation on the inert anode can be eliminated by the high OER activity of the active anode. The constructed full electrolytic cell only needs a low potential of 1.498 V to achieve 10 mA/cm 2 for water electrolysis. The reported promotion effect of phenol degradation by OER as well as the improved anode resistance to deactivation offer new insights into efficient and robust waste-to-resource electrolysis system for water treatment.

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