Synthesis of Gold-Platinum Core-Shell Nanoparticles Assembled on a Silica Template and Their Peroxidase Nanozyme Properties.

Bimetallic nanoparticles are important materials for synthesizing multifunctional nanozymes. A technique for preparing gold-platinum nanoparticles (NPs) on a silica core template (SiO ₂ @Au@Pt) using seed-mediated growth is reported in this study. The SiO ₂ @Au@Pt exhibits peroxidase-like nanozyme activity has several advantages over gold assembled silica core templates (SiO ₂ @Au@Au), such as stability and catalytic performance. The maximum reaction velocity (V _max ) and the Michaelis-Menten constants (K _m ) were and 2.1 × 10 ^-10 M ^-1 ∙s ^-1 and 417 µM, respectively. Factors affecting the peroxidase activity, including the quantity of NPs, solution pH, reaction time, and concentration of tetramethyl benzidine, are also investigated in this study. The optimization of SiO ₂ @Au@Pt NPs for H ₂ O ₂ detection obtained in 0.5 mM TMB; using 5 µg SiO ₂ @Au@Pt, at pH 4.0 for 15 min incubation. H ₂ O ₂ can be detected in the dynamic liner range of 1.0 to 100 mM with the detection limit of 1.0 mM. This study presents a novel method for controlling the properties of bimetallic NPs assembled on a silica template and increases the understanding of the activity and potential applications of highly efficient multifunctional NP-based nanozymes.