Neiva Joana, Benzarti Zohra, Carvalho Sandra, Devesa Susana
CEMMPRE, ARISE, Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, 3030-788 Coimbra, Portugal.
Laboratory of Multifunctional Materials and Applications (LaMMA), Department of Physics, Faculty of Sciences of Sfax, University of Sfax, Soukra Road km 3.5, B.P. 1171, Sfax 3000, Tunisia.
Materials (Basel). 2024 Nov 22;17(23):5709. doi: 10.3390/ma17235709.
This study investigates the structural, chemical, and morphological properties of CuO nanoparticles synthesized via a green synthesis route using - cladode extract, with a focus on the effects of stepwise versus direct calcination. Raman spectroscopy revealed the presence of CuO, NaCO, and NaSO, with the latter two being associated with elements inherited from the cactus extracts. XRD patterns confirmed the presence of crystalline CuO and NaCO phases, with the low content of NaSO inferred to be amorphous. Rietveld refinement estimated a CuO content of approximately 77% in the stepwise-calcined sample and 75% in the directly calcined sample, with lattice parameters closely aligning with reference values. SEM micrographs revealed a tendency for CuO nanoparticles to aggregate, likely due to high surface energy and interaction with the viscous plant extract used in the green synthesis. Crystallite size estimates, along with morphological observations, suggest that stepwise calcination enhances crystallinity and particle definition without altering the fundamental nanoparticle morphology. These findings highlight the influence of calcination method and natural extracts on the composition and morphology of green-synthesized CuO nanoparticles, offering insights into potential applications, namely in microelectronics, due to their promising dielectric properties.
本研究调查了通过使用仙人掌叶提取物的绿色合成路线合成的氧化铜纳米颗粒的结构、化学和形态特性，重点关注分步煅烧与直接煅烧的效果。拉曼光谱显示存在氧化铜、碳酸钠和硫酸钠，后两者与从仙人掌提取物中继承的元素有关。X射线衍射图谱证实存在结晶氧化铜和碳酸钠相，推断硫酸钠含量低为非晶态。Rietveld精修估计分步煅烧样品中氧化铜含量约为77%，直接煅烧样品中为75%，晶格参数与参考值紧密吻合。扫描电子显微镜图像显示氧化铜纳米颗粒有聚集趋势，这可能是由于表面能高以及与绿色合成中使用的粘性植物提取物相互作用所致。微晶尺寸估计以及形态观察表明，分步煅烧可提高结晶度和颗粒清晰度，而不会改变基本的纳米颗粒形态。这些发现突出了煅烧方法和天然提取物对绿色合成的氧化铜纳米颗粒的组成和形态的影响，鉴于其有前景的介电性能，为潜在应用（即在微电子领域）提供了见解。
