Flow-Through Nanozymes With Dynamic Modulated Cavity for Photoelectrocatalytic Selective Debromination

Nanozymes represent a novel and promising technology for selective pollutant removal in wastewater treatment. Here, nanozymes with dynamic modulated active cavities on single-crystal Co₃O₄ (di-Co₃O₄) is developed. These nanozymes exhibit exceptional selectivity and catalytic efficiency in removing polybrominated diphenyl ethers (PBDEs), achieving 100% removal of a specific class of PBDEs, preferentially adsorbing less brominated PBDEs to effectively eliminate their toxicity. Experimental and theoretical calculations reveal that this enzyme-like specificity arises from Co─Br chemical bond interactions within the active cavities, accommodating bromine atoms with low spatial resistance. In-situ X-ray absorption spectroscopy is employed to monitor the photoelectrocatalytic process, demonstrating that bromine atoms occupy the active cavities and that divalent cobalt serves as the targeted adsorption site, facilitating efficient debromination at -0.6 V (versus SCE). The integration of flow cells enhances the removal efficiency of di-Co₃O₄ and synergistically improves their anti-interference capability against co-existing contaminants in complex systems. This work offers a novel design strategy for wastewater remediation and advances the dynamic tracking of photoelectrocatalytic processes.