Dzimitrowicz Anna, Cyganowski Piotr, Pohl Pawel, Milkowska Weronika, Jermakowicz-Bartkowiak Dorota, Jamroz Piotr
Department of Analytical Chemistry and Chemical Metallurgy, Wroclaw University of Science and Technology, Wybrzeze St. Wyspianskiego 27, 50-370 Wroclaw, Poland.
Department of Process Engineering and Technology of Polymer and Carbon Materials, Wroclaw University of Science and Technology, Wybrzeze St. Wyspianskiego 27, 50-370 Wroclaw, Poland.
Nanomaterials (Basel). 2020 Jun 1;10(6):1088. doi: 10.3390/nano10061088.
Because cold atmospheric pressure plasma (CAPP)-based technologies are very useful tools in nanomaterials synthesis, in this work we have connected two unique in their classes approaches-a CAPP-based protocol and a green synthesis method in order to obtain stable-in-time gold nanoparticles (AuNPs). To do so, we have used an aqueous leave extract and an aqueous root extract (untreated or treated by CAPP) to produce AuNPs, suitable for catalytical uses. Firstly, we have adjusted the optical properties of resulted AuNPs, applying UV/Vis absorption spectrophotometry (UV/Vis). To reveal the morphology of Au nanostructures, transmission electron microscopy (TEM) in addition to energy dispersive X-ray scattering (EDX) and selected area X-ray diffraction (SAED) was utilized. Moreover, optical emission spectrometry (OES) in addition to a colorimetric method was used to identify and determine the concentration of selected RONS occurring at the liquid-CAPP interface. Additionally, attenuated total reflectance Fourier transform-infrared spectroscopy (ATR FT-IR) was applied to reveal the active compounds, which might be responsible for the AuNPs surface functionalization and stabilization. Within the performed research it was found that the smallest in size AuNPs were synthesized using the aqueous root extract, which was activated by direct current atmospheric pressure glow discharge (dc-APGD), generated in contact with a flowing liquid cathode (FLC). On the contrary, taking into account the aqueous leave extract, the smallest in size AuNPs were synthesized when the untreated by CAPP aqueous leave extract was involved in the Au nanostructures synthesis. For catalytical studies we have chosen AuNPs produced using the aqueous root extract activated by FLC-dc-APGD as well as AuNPs synthesized using the aqueous leave extract also activated by FLC-dc-APGD. Those NPs were successfully used as homogenous catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).
由于基于冷大气压力等离子体（CAPP）的技术在纳米材料合成中是非常有用的工具，在本工作中，我们将两类独特的方法——基于CAPP的方案和绿色合成方法相结合，以获得随时间稳定的金纳米颗粒（AuNP）。为此，我们使用了水叶提取物和水根提取物（未处理或经CAPP处理）来制备适用于催化用途的AuNP。首先，我们应用紫外/可见吸收分光光度法（UV/Vis）来调节所得AuNP的光学性质。为了揭示金纳米结构的形态，除了能量色散X射线散射（EDX）和选区X射线衍射（SAED）外，还利用了透射电子显微镜（TEM）。此外，除了比色法外，还使用了光发射光谱法（OES）来识别和测定在液体-CAPP界面处产生的选定活性氧氮化物（RONS）的浓度。此外，还应用衰减全反射傅里叶变换红外光谱（ATR FT-IR）来揭示可能负责AuNP表面功能化和稳定化的活性化合物。在所进行的研究中发现，使用与流动液体阴极（FLC）接触产生的直流大气压力辉光放电（dc-APGD）激活的水根提取物合成了尺寸最小的AuNP。相反，考虑到水叶提取物，当未经过CAPP处理的水叶提取物参与金纳米结构合成时，合成了尺寸最小的AuNP。为了进行催化研究，我们选择了使用FLC-dc-APGD激活的水根提取物制备的AuNP以及同样由FLC-dc-APGD激活的水叶提取物合成的AuNP。这些纳米颗粒成功地用作将4-硝基苯酚（4-NP）还原为4-氨基苯酚（4-AP）的均相催化剂。
