Carbon dot enhanced peroxidase-like activity of platinum nanozymes

As one of the most intriguing nanozymes, the platinum (Pt) nanozyme has attracted tremendous research interest due to its various catalytic activities but its application is still limited by its poor colloidal stability and low affinity to substrates. Here, we design a highly stable Pt@carbon dot (Pt@CD) hybrid nanozyme with enhanced peroxidase (POD)-like activity (specific activity of 1877 U mg^-1). The Pt@CDs catalyze the decomposition of hydrogen peroxide (H₂O₂) to produce singlet oxygen and hydroxyl radicals and exhibit high affinity to H₂O₂ and high specificity to 3,3',5,5'-tetramethyl-benzidine. We reveal that both the hydroxyl and carbonyl groups of CDs could coordinate with Pt²⁺ and then regulate the charge state of the Pt nanozyme, facilitating the formation of Pt@CDs and improving the POD-like activity of Pt@CDs. Colorimetric detection assays based on Pt@CDs for H₂O₂, dopamine, and glucose with a satisfactory detection performance are achieved. Moreover, the Pt@CDs show a H₂O₂-involving antibacterial effect by destroying the cell membrane. Our findings provide new opportunities for designing hybrid nanozymes with desirable stability and catalytic performance by using CDs as nucleating templates and stabilizers.