This work describes a simple single-step method for green synthesis of colloidal gold nanoparticles (AuNPs) using Litsea cubeba (LC) fruit extract as a reducing as well as stabilizing agent simultaneously. Major parameters affecting the formation of LC-AuNPs, including gold ion concentration, reaction time, and reaction temperature were optimized using ultraviolet-visible (UV-Vis) measurements at a characteristic maximum absorbance of 535 nm. The functional groups responsible for reducing gold ions and capping AuNPs were examined by Fourier-transform infrared (FTIR) spectroscopy. Powder X-ray diffraction (XRD) analysis revealed the crystalline nature of AuNPs. Transmission electron microscopy (TEM) measurements showed that the biosynthesized LC-AuNPs were mostly spherical with an average size of 8-18 nm. The nanoparticles also demonstrated excellent ultrarapid catalytic activity for the complete reduction of 4-nitrophenol to p-aminophenol in the presence of NaBH₄ within 10 min with a reaction rate constant of 0.348 min^-1.

中文翻译：

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荔枝果实提取物生物合成金纳米颗粒催化还原4-硝基苯酚

这项工作描述了使用Litsea cubeba绿色合成胶体金纳米颗粒（AuNPs）的简单单步方法（LC）水果提取物同时作为还原剂和稳定剂。使用紫外可见（UV-Vis）测量以535 nm为特征最大吸光度来优化影响LC-AuNPs形成的主要参数，包括金离子浓度，反应时间和反应温度。通过傅里叶变换红外（FTIR）光谱检查负责还原金离子和封端AuNPs的官能团。粉末X射线衍射（XRD）分析显示了AuNPs的晶体性质。透射电子显微镜（TEM）测量表明，生物合成的LC-AuNPs大多为球形，平均大小为8-18 nm。在NaBH存在下，纳米颗粒还具有出色的超快催化活性，可将4-硝基苯酚完全还原为对氨基苯酚10min内为₄，反应速率常数为0.348min ^-1。