Nanozyme-coupled photoelectrocatalytic system based on peroxidase-mimetic BiOI cathode and WO3 photoanode for efficient degradation of 3-chlorophenol

As an advanced oxidation technology, solar light-driven photoelectrocatalysis has been considered to be a sustainable method for wastewater treatment. Meanwhile, peroxidase-mimetic nanozymes have emerged as a promising tool for environmental remediation. In this work, we aimed to combine nanozyme catalysis with solar light-driven photoelectrocatalysis to achieve efficient degradation of persistent contaminant, using 3-chlorophenol (3-CP) as the representative pollutant. In the designed system, WO3 nanoplate photoanode displayed high photoelectrocatalytic activity for both 3-CP degradation and H2O2 production under simulated solar light. Furthermore, peroxidase-like BiOI with nanoflower structure was immobilized on hydrophobic carbon cathode to catalyze the oxidation of 3-CP by in situ generated H2O2. The constructed nanozyme-coupled photoelectrocatalytic system exhibited a satisfactory 3-CP degradation efficiency of 91.1 % after 90-min treatment. In addition, the possible reaction mechanisms and degradation pathways of 3-CP in such a system were discussed.