Department of Chemistry , Capital Normal University , Beijing 100048 , China.
ACS Appl Mater Interfaces. 2018 Sep 26;10(38):32567-32578. doi: 10.1021/acsami.8b10560. Epub 2018 Sep 13.
In this study, we present a three-in-one catalytic platform for intrinsic oxidase-, peroxidase-, and catalase-like activity, which is enabled by epitaxial growth of the MoS nanosponge on 2D Co(OH) nanoflakes [2D Co(OH) NFs] (CoMo hybrids). First, the 2D Co(OH) NFs are stripped from hierarchical three-dimensional Co(OH) nanoflowers which are synthesized in an eco-friendly way via one-step surfactant-free chemical route. Next, the porous MoS nanosponge is decorated on the 2D Co(OH) NFs' surface using a solvothermal process forming heterogeneous nanostructured CoMo hybrids. Finally, because of the host-guest interaction, that is, after the epitaxial growth of spongy MoS on 2D Co(OH) NFs, the heterogeneous nanostructure of CoMo hybrids exhibits unpredictable triple-enzyme mimetic activity simultaneously. The mechanisms of the oxidase-like properties are investigated by density functional theory (DFT) calculations, and it is discovered that a simple reaction/dissociation of O absorbed on Co-Mo thin films can explain the enhanced oxidase-like activity of the CoMo hybrids. In addition, the CoMo hybrids are also reproducible, stable, and reusable, that is, after 10 cycle uses, >90% mimic enzyme activity of the CoMo hybrids is still maintained. The oxidase-like activity of the CoMo hybrids enables it to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) producing the blue oxTMB, which can selectively oxidize ascorbic acid (AA) and pave a new avenue for colorimetric sensing of AA. The proposed colorimetric strategy has been successfully utilized to measure AA in rat brain during the cerebral calm/ischemia process. Our findings provide in-depth insight into the future research of enzyme-like activities and might help to elucidate the mechanism and understand the role of epitaxial growth on the properties and application of hybrid nanostructures.
在这项研究中，我们提出了一种三功能催化平台，具有内在的氧化酶、过氧化物酶和过氧化氢酶样活性，这是通过将 MoS 纳米海绵外延生长在二维 Co(OH) 纳米薄片[2D Co(OH) NF]（CoMo 杂化物）上实现的。首先，将二维 Co(OH) NF 从通过一步无表面活性剂的环保化学途径合成的分级三维 Co(OH) 纳米花中剥离出来。接下来，使用溶剂热法在 2D Co(OH) NF 表面上装饰多孔 MoS 纳米海绵，形成异质纳米结构的 CoMo 杂化物。最后，由于主客体相互作用，即海绵状 MoS 在二维 Co(OH) NF 上外延生长后，CoMo 杂化物的异质纳米结构同时表现出不可预测的三酶模拟活性。通过密度泛函理论（DFT）计算研究了类氧化酶性质的机制，发现 O 在 Co-Mo 薄膜上的简单反应/解离可以解释 CoMo 杂化物增强的类氧化酶活性。此外，CoMo 杂化物还具有可重复性、稳定性和可重复使用性，即在 10 次循环使用后，CoMo 杂化物的模拟酶活性仍保持在>90%。CoMo 杂化物的类氧化酶活性使其能够氧化 3,3',5,5'-四甲基联苯胺（TMB）产生蓝色 oxTMB，该反应可选择性地氧化抗坏血酸（AA），为 AA 的比色传感开辟了新途径。所提出的比色策略已成功用于测量脑平静/缺血过程中大鼠大脑中的 AA。我们的发现深入了解了酶样活性的未来研究，并可能有助于阐明外延生长对混合纳米结构性质和应用的作用机制。
