Defect-Engineered CoFe Layered Double Hydroxide Quantum Dots: Oxygen Vacancy-Driven Boost in Peroxidase-Mimic Catalysis for Multiplex Biomarker Sensing

Defects in nanomaterials are crucial for modifying the catalytic microenvironment, thus enhancing nanozyme catalytic efficiency. Combining defect engineering with layered double hydroxides (LDHs) nanozymes holds promise for expanding catalytic applications. We employed density functional theory (DFT) to systematically study how O vacancies regulate the peroxidase (POD)-like activity of CoFe LDHs nanozymes. Results show that O vacancies significantly alter the catalyst’s surface electronic configuration, optimize the adsorption energy of reactants, lower the reaction energy barrier, and boost POD activity. We synthesized O-vacancy-rich CoFe LDHs quantum dots, verified their excellent catalytic activity, and constructed a sensitive colorimetric detection platform for glucose, glutathione, and nitrite, enabling on-site detection via smartphone integration. This study offers an efficient and cost-effective solution for multiplex biomarker detection, laying the foundation for personalized medicine and point-of-care diagnostics.