Atomic Chromium Coordinated Graphitic Carbon Nitride for Bioinspired Antibiofouling in Seawater

Artificial nanozymes exerting enzyme functionality are recognized as promising alternatives of natural enzymes in biomimetic chemistry. Natural haloperoxidases that utilize hydrogen peroxide (H2O2) to catalytically convert halide into strong biocidal hypohalous acid hold great promise for thwarting biofouling, while their practical application remains highly questionable as instability of natural enzymes and inadequate H2O2. Herein a semiconducting nanozyme consisting of chromium single atoms coordinated on carbon nitride (Cr-SA-CN) that performs bifunctional roles of nonsacrificial H2O2 photosynthesis and haloperoxidase-mimicking activity for antibiofouling is constructed. Such nanozyme is capable of generating H2O2 from water and O-2 upon visible-light illumination, and then sustainably self-supplying H2O2 for haloperoxidase-mimicking reaction in a sequential manner. This dual-activity Cr-SA-CN overcomes H2O2 dilemma and yields hypobromous acid continuously, inducing remarkable bactericidal capability. When used as an eco-friendly coating additive, it is successfully demonstrated that Cr-SA-CN enables an inert surface against marine biofouling. Thereby, this study not only illustrates an attractive strategy for antibiofouling but also opens an avenue to construct valuable nanoplatform with multifunctionality for future applications.

Automated summary

This study presents the construction of a chromium single atom nanozyme capable of performing nonsacrificial H2O2 photosynthesis and haloperoxidase-mimicking activity for antibiofouling. The nanozyme can generate H2O2 from water and O-2 under visible-light illumination, and sustainably supply H2O2 for a haloperoxidase-mimicking reaction. This dual-activity nanozyme overcomes the instability of natural enzymes and inadequate H2O2, resulting in continuous production of hypobromous acid with remarkable bactericidal capability. The application of the nanozyme as an eco-friendly coating additive demonstrates its effectiveness in preventing marine biofouling.