Peroxidase‐Mimicking Platinum and Palladium Nanorattles: Nanozymes for Ultrasensitive Detection of Hydrogen Peroxide and Glucose

Nanozymes, engineered nanomaterials with enzyme‐mimicking properties, present a promising alternative to natural enzymes. Noble metal nanoparticles, particularly those with high standard electrode potential, demonstrate the effective catalysis of H ₂ O ₂ to produce •OH radicals. These nanozymes surpass iron‐based counterparts in inertness and nonleaching property but faces reduced catalytic activity due to limited surface area as result of surfactant‐induced active site occlusion, necessitating nanoparticle designs that maximize active sites while preventing aggregation. In this regard, two bimetallic nanorattles (NRT), palladium (Au‐Octa@Pd NRT) and a platinum nanorattles (Au‐Octa@Pt NRT), are synthesized, with solid gold octahedron core and porous cubic Pd or Pt shell, respectively. The peroxidase‐like activity of these nanorattles are evaluated and compared with Horseradish peroxidase (HRP) using the Michaelis‐Menten kinetics. Synthesized Au‐Octa@Pt NRT shows a higher affinity ( K _m = 0.384 M) toward 3,3′, 5,5′‐tetramethylbenzidine as a substrate compared to Au‐Octa@Pd NRT ( K _m = 0.415 M) and HRP ( K _m = 0.497 M). Further Au‐Octa@Pt NRT demonstrates high sensitivity, detecting H ₂ O ₂ up to 0.3 μM and glucose with Au‐Octa@Pt NRT‐glucose oxidase (GO _x ) cascade up to 0.01 μM. Au‐Octa@Pt NRT exhibits superior catalytic activity and stability across a broad temperature range, making it promising for ultrasensitive hydrogen peroxide and glucose detection in various biochemical and clinical settings.