Bioinspired Allosteric Peroxidase-like Enzyme with Dynamic 3D Catalytic Centers for Advanced Water Treatment

Natural enzymatic catalysis is governed by the precise three-dimensional (3D) coordination environments of active sites to create spatially optimized reaction centers. Inspired by this biological architecture, we engineered a biomimetic enzyme mimicking heme peroxidase (POD) functionality to reduce overreliance on transition metals in advanced water treatment. Integrating the natural cofactor hemin with C₃N₄ nanosheets via π-π stacking and axial Fe-N coordination─mimicking amino acid microenvironments through scalable self-assembly─we constructed a dynamic 3D catalytic center analogous to natural enzyme pockets. The synthesized biomimetic catalyst demonstrated remarkable POD-like activity enhancements─150-fold and 40-fold compared to free hemin when activated H₂O₂ and peroxymonosulfate (PMS), respectively. Mechanistic studies revealed that axial coordination induced nonplanar deformation of the hemin, weakening d-π conjugation between Fe d-orbitals and the porphyrin π-system. Notably, a biomimetic allosteric regulation triggered by this structural distortion was first proposed for water treatment, accelerating the rate-limiting sulfate desorption step during PMS activation. The catalyst also exhibited exceptional structural stability, and sustained performance in complex water matrices and high-salinity environments, achieving >80% pollutant removal over 150 h in continuous-flow tests. This catalytic structure design sets a benchmark for efficient biomimetic enzymes, bridging biocatalysis and synthetic catalysis, and offers scalable, nature-inspired solutions for water purification technologies.