Enhanced Peroxidase-like Activity of CuS Hollow Nanocages by Plasmon-Induced Hot Carriers and Photothermal Effect for the Dual-Mode Detection of Tannic Acid

High catalytic activity is one of the necessary parameters for nanozymes to substitute for natural enzymes. It remains a great challenge to improve the specific enzyme-like activity of nanozymes as much as possible using the characteristics of nanomaterials for avoiding complexity and introducing additional uncertainties. Here, by combining the peroxidase (POD)-like activity and plasmon properties of CuS hollow nanocages (CuS HNCs), we demonstrate the feasibility of modulating the catalytic activity of nanozymes by the localized surface plasmon resonance (LSPR) effect. Rough surfaces and hollow-cage structures endow CuS HNCs with abundant hot spots to produce strong LSPR in the near-infrared (NIR) region, which makes the CuS HNCs simultaneously generate plentiful high-energy hot carriers and thermal effect to mediate H₂O₂ cleavage to yield the reactive oxide species (ROS) as well as speed up the reaction, leading to a dramatically enhanced POD-like activity. Based on the light-enhanced catalytic activity and high photothermal efficiency of the reaction system, a dual-mode strategy for detecting tannic acid (TA) is developed and successfully applied to determine the content of TA in different kinds of teas. This work not only provides a novel path for tuning the specific enzyme-like activity of nanomaterials but also shows a perspective for dual-mode sensing based on a photoinduced plasmon-enhanced effect.