Surface Hot‐Electron Transfer‐Driven Site‐Specific Growth of Pt Nanoisland onto Au NR@CeO 2 Dumbbells With Exceptional H 2 O 2 Affinity for Ultra‐Sensitive Vitro Diagnosis

Abstract The affinity between H 2 O 2 and nanozymes in vitro diagnostic applications significantly influences their respective detection performance. However, the limited affinity of most existing nanozymes for H 2 O 2 , often characterized by a high Michaelis‐Menten constant ( K m ), arises from uncontrolled structural modulation, inadequate surface defects, and low d ‐band center, consequently compromising the efficacy of in vitro diagnostics. Herein, a multi‐dimensional strategy for designing high‐performance nanoprobes by integrating element doping, structural regulation, and surface engineering is proposed. Notably, the linker‐coupled laser‐induced growth and electron transfer mechanism plays a crucial role in activating Au nanorod (NR)@CeO 2 dumbbell‐like substrates. This process facilitates the site‐specific growth of discontinuous Pt nanoislands possessing a high density of defects and an exceptional specific surface area, thereby enhancing the affinity of the resulting Au NR@CeO 2 @Pt nanozymes toward H 2 O 2 . Through a structure‐surface‐electronic cooperative design approach, this study systematically addresses the intrinsic limitations in catalytic efficiency of conventional nanozymes, providing novel insights for the development of highly sensitive in vitro diagnostic platforms and next‐generation biomedical nanoprobes.