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

Cu 2+ -functionalized carbon nitride nanoparticles (Cu 2+ –g-C 3 N 4 NPs), ∼200 nm, and Cu 2+ –carbon dots (Cu 2+ –C-dots), ∼8 nm, act as horseradish peroxidase-mimicking catalysts. The nanoparticles catalyze the generation of chemiluminescence in the presence of luminol/H 2 O 2 and catalyze the oxidation of dopamine by H 2 O 2 to form aminochrome. The Cu 2+ –g-C 3 N 4 -driven generation of chemiluminescence is used to develop a H 2 O 2 sensor and is implemented to develop a glucose detection platform and a sensor for probing glucose oxidase. Also, the Cu 2+ –C-dots are functionalized with the β-cyclodextrin (β-CD) receptor units. The concentration of dopamine, at the Cu 2+ –C-dots’ surface, by means of the β-CD receptor sites, leads to a 4-fold enhancement in the oxidation of dopamine by H 2 O 2 to yield aminochrome compared to that of the unmodified C-dots.