Deciphering the Mechanisms of Photo-Enhanced Catalytic Activities in Plasmonic Pd-Au Heteromeric Nanozymes for Colorimetric Analysis

The growing demand for highly active nanozymes in various fields has led to the development of several strategies to enhance their activity. Plasmonic enhancement, a strategy used in heterogenous catalysis, represents a promising strategy to boost the activity of nanozymes. Herein, Pd-Au heteromeric nanoparticles (Pd-Au dimers) with well-defined heterointerfaces have been explored as plasmonic nanozymes. As a model system, the Pd-Au dimers with integrated peroxidase (POD)-like activity and plasmonic activity are used to investigate the effect of plasmons on enhancing the activity of nanozymes under visible light irradiation. Mechanistic studies revealed that the generation of hot electron-hole pairs plays a dominant role in plasmonic effect, and it greatly enhances the decomposition of H2O2 to the reactive oxygen species (ROS) intermediates (& BULL;OH, & BULL;O2- and 1O2), leading to elevated POD-like activity of the Pd-Au dimers. Finally, the Pd-Au dimers are applied in the plasmon-enhanced colorimetric method for the detection of alkaline phosphatase, exhibiting broad linear range and low detection limit. This study not only provides a straightforward approach for regulating nanozyme activity through plasmonic heterostructures but also sheds light on the mechanism of plasmon-enhanced catalysis of nanozymes. In this study, Pd-Au plasmonic heteromeric nanomaterials with distinct heterointerface are used as peroxidase nanozymes. The main contribution of electron-hole pairs generated by light to the catalytic process is proved, and the key ROS intermediates generated by plasma excitation are determined. Based on this, a method for detecting alkaline phosphatase by plasmon-enhanced colorimetry is established.image