A perylenediimide modified SiO₂@TiO₂ yolk-shell light-responsive nanozyme: Improved peroxidase-like activity for H₂O₂...

Although light-responsive nanozyme have been widely used in colorimetric sensing, some limitations such as poor catalytic activity, low detection efficiency, and unclear structure-activity relationships remain unresolved. Herein, we prepared an excellent light-responsive peroxidase (POD) mimic, perylenediimide (PDI-OH) modified SiO₂ @TiO₂ yolk-shell spheres (SiO₂ @TiO₂/PDI-OH), based on DFT-assisted design. The experiment and DFT calculation revealed that the enhanced POD-like activity was mainly attributed to a suitable built-in electric field among adjacent PDI-OH molecules on the surface of the SiO₂ @TiO₂ and the unique yolk-shell structure with more reaction sites of SiO₂ @TiO₂. Consequently, the highly selective and ultrasensitive detection of H₂O₂ is achieved with a detection limit (LOD) of 7.6 × 10^-8M. Further, the selective detection of sarcosine with LOD of 1.2 × 10^-7 M was also achieved by introducing sarcosine oxidase (SOx). This colorimetric assay is successfully applied to selectively detect H₂O₂ and sarcosine levels in real samples. Controlled response time, anti-interference, and the robustness of the developed colorimetric sensor are the key advantages. And the present work firstly clarifies the effect of PDIs substituents on the POD-like activity of light-responsive nanozymes and provided new guidelines to develop high-performance nanozymes for hazardous substances detection.