Mimicking Horseradish Peroxidase Functions Using Cu²⁺-Modified Carbon Nitride Nanoparticles or Cu²⁺-Modified Carbon Dots as Heterogeneous Catalysts

Cu²⁺-functionalized carbon nitride nanoparticles (Cu²⁺-g-C₃N₄ NPs), ∼200 nm, and Cu²⁺-carbon dots (Cu²⁺-C-dots), ∼8 nm, act as horseradish peroxidase-mimicking catalysts. The nanoparticles catalyze the generation of chemiluminescence in the presence of luminol/H₂O₂ and catalyze the oxidation of dopamine by H₂O₂ to form aminochrome. The Cu²⁺-g-C₃N₄-driven generation of chemiluminescence is used to develop a H₂O₂ sensor and is implemented to develop a glucose detection platform and a sensor for probing glucose oxidase. Also, the Cu²⁺-C-dots are functionalized with the β-cyclodextrin (β-CD) receptor units. The concentration of dopamine, at the Cu²⁺-C-dots' surface, by means of the β-CD receptor sites, leads to a 4-fold enhancement in the oxidation of dopamine by H₂O₂ to yield aminochrome compared to that of the unmodified C-dots.