Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
National Synchrotron Radiation Research Centre, Hsinchu, 30076, Taiwan.
Small. 2022 Feb;18(5):e2104844. doi: 10.1002/smll.202104844. Epub 2021 Nov 25.
Single-atom catalysts have attracted attention in the past decade since they maximize the utilization of active sites and facilitate the understanding of product distribution in some catalytic reactions. Recently, this idea has been extended to single-atom nanozymes (SAzymes) for the mimicking of natural enzymes such as horseradish peroxidase (HRP) often used in bioanalytical applications. Herein, it is demonstrated that those SAzymes without constructing the reaction pocket of HRP still undergo the OH radical-mediated pathway like most of the reported nanozymes. Their positively charged single-atom centers resulting from support electronegative oxygen/nitrogen hinder the reductive conversion of H O to OH radicals and hence display low activity per site. In contrast, it is found that this step can be facilitated over their metallic counterparts on cluster nanozymes with much higher site activity and atom efficiency (cf. SAzymes with 100% atom utilization). Besides the mimicking of HRP in glucose detection, cluster nanozymes are also demonstrated as a better oxidase mimetic for glutathione detection.
单原子催化剂在过去十年中引起了人们的关注，因为它们最大限度地利用了活性位点，并有助于理解某些催化反应中的产物分布。最近，这一想法被扩展到了单原子纳米酶（SAzymes），以模拟辣根过氧化物酶（HRP）等天然酶，这种酶常用于生物分析应用。本文证明，那些没有构建 HRP 反应口袋的 SAzymes 仍然像大多数报道的纳米酶一样，经历 OH 自由基介导的途径。它们带正电荷的单原子中心源于支撑体的电负性氧/氮，阻碍了 H2O 向 OH 自由基的还原转化，因此表现出低的每个位点活性。相比之下，人们发现，在具有更高位点活性和原子效率的簇状纳米酶上（相比 SAzymes 具有 100%的原子利用率），这一步可以得到促进。除了在葡萄糖检测中模拟 HRP 外，簇状纳米酶还被证明是一种更好的谷胱甘肽检测氧化酶模拟物。
