Ag-Ag2S/MoS2的制备及在无酶电化学过氧化氢传感中的应用

Fabrication and application of Ag-Ag2S/MoS2-based composite for nonenzymatic electrochemical detection of hydrogen peroxide

本文设计并制备了一种用于无酶电化学过氧化氢传感的新型银-硫化银/硫化钼复合材料(Ag-Ag2S/MoS2).通过将单独合成的MoS2水分散液和Ag纳米分散液进行混合,利用自组装的方法实现了Ag-Ag2S/MoS2复合材料的制备.结果发现, Ag-Ag2S纳米颗粒均匀生长在由多层片状MoS2堆积形成的花瓣上, Ag2S主要存在于Ag纳米颗粒和MoS2片层的接触界面处.将此复合材料用于电化学传感时,修饰的电极表现出诱人的无酶电化学H2O2传感性能,不但具有极宽的线性区间范围(0.01~160 mmol/L),而且保持很好的灵敏度17.1μA (mmol/L)-1cm-2和较小的最低检测限4.8μmol/L.这种优良的性能归因于Ag, Ag2S颗粒和MoS2片层三者间的协同作用:Ag和MoS2本身都具有良好的过氧化氢催化活性, Ag纳米颗粒和1T相MoS2能显著提高复合材料的导电性能,界面形成的少量Ag2S为Ag和MoS2间的电子传输提供了通道.进一步的分析表明,这种基于Ag-Ag2S/MoS2复合材料的传感器还表现出卓越的选择性、良好的稳定性和重现性.

In this study, novel Ag-Ag2S/MoS2 composites were designed and prepared for the nonenzymatic electrochemical detection of hydrogen peroxide. The composites were obtained by the self-assembly of a MoS2 aqueous solution and Ag nanodispersions. In the composite, the multilayered MoS2 was distributed as a petal shape, and Ag-Ag2S nanoparticles(NP) with a size of 30 nm × 20 nm were uniformly grown on the petal-like layer. Low-content Ag2S existed mainly at the interface between the Ag NPs and the MoS2 sheets. The Ag-Ag2S/MoS2 composite modified electrode exhibited a good enzyme-free electrochemical sensing performance for H2O2 with an extremely wide linear range of 0.01–160 mmol/L, a good sensitivity of 17.1 μA(mmol/L)-1 cm-2, and a minimum detection limit of 4.8 μmol/L. The excellent sensing properties of the composite were probably due to the synergistic effect of the combination of Ag, Ag2S nanoparticles, and MoS2. Not only did Ag and 1 T-phase MoS2 have better catalytic activity than hydrogen peroxide, but they could also significantly improve the conductive properties of the composites. A small amount of Ag2S also provided a pathway for electron transport between Ag and MoS2. The sensor based on Ag-Ag2S/MoS2 composite also exhibited good catalytic activity, excellent selectivity, good stability, and reproducibility.