Light-activated nanozymes can provide a wealth of new opportunities for the chemical industry and biotechnology. However, present remote-controlled catalytic systems are still far from satisfactory. Herein, we present an interesting example of applying ultrathin Pd nanosheets (Pd NSs) as a light-controllable peroxidase mimic. Since most of Pd atoms are exposed on their surface, Pd NSs with a thickness of 1.1 nm possess high peroxidase-like activity. More importantly, under light excitation, such intrinsic activity can be further activated by a nearly 2.4- to 3.2-fold. Such a phenomenon can be ascribed to the unique optical property of ultrathin Pd NSs, which can efficiently capture photons to generate hot electrons via surface plasmon resonance effect and thus promote the in situ decomposition of H₂O₂ into reactive oxygen species radicals (O*). This enhanced catalysis can also be used for real-time and highly sensitive colorimetric detection of H2O2. We expect our work can provide valuable insights into the rational design of artificial nanozymes with controllable and efficient activity in biomedical diagnostics, drug delivery, and environmental chemistry.

光活化的纳米酶可以为化学工业和生物技术提供大量新的机会。但是，目前的遥控催化系统仍然远远不能令人满意。在这里，我们提出了一个有趣的例子，将超薄Pd纳米片（Pd NSs）用作光可控的过氧化物酶模拟物。由于大多数Pd原子暴露在其表面上，因此厚度为1.1 nm的Pd NSs具有高的过氧化物酶样活性。更重要的是，在光激发下，这种内在活性可以进一步被激活近2.4到3.2倍。这种现象可归因于超薄Pd NSs的独特光学性质，它可以有效捕获光子，通过表面等离子体共振效应产生热电子，从而促进H ₂ O的原位分解。₂转变成活性氧自由基（O *）。这种增强的催化作用还可用于H2O2的实时和高灵敏度比色检测。我们希望我们的工作能够为人工纳米酶的合理设计提供有价值的见解，并在生物医学诊断，药物递送和环境化学中具有可控和有效的活性。