ABSTRACT

The phytosynthesis of metal oxides nanoparticles (NPs) has been extensively reported; yet mechanism involved and incorporated bioactive compounds in the synthesized NPs are still need to be investigated. In this regard, here an efficient sustainable co-precipitation synthesis of zinc oxide nanoparticles (ZnO NPs) has been developed, employing hydrothermal reactions, using organic compounds of Nasturtium officinale leaves. Pure hexagonal wurtzite ZnO was identified by X-ray diffraction and NPs in the size range of 50–60 nm were observed by field emission scanning electron microscopy. X-ray photoelectron spectroscopy revealed surface modification of ZnO by functional groups associated with the incorporated bio active compounds of Nasturtium officinale. The phyto-functionalized ZnO NPs having anoptical direct band gap of 3.29 eV and optical band gap energy of 2.85 eV were evaluated by cyclic voltammetry at various scan rates, galvanostatic charge–discharge at a range of current densities and electrochemical impedance spectroscopy (Z′ vs. Z″ and Z vs. frequency) in aqueous electrolyte. The fabricated ZnO-based electrode revealed a specific capacitance of 86.5 F/g at 2 mV/s with 97% coulombic efficiency for 2000 cycles. The good electrochemical conductivity was demonstrated by lower internal resistance of 1.04 Ω. Therefore, the present study suggested the significant potential of organic compounds incorporated ZnO NPs towards supercapacitor.

摘要

金属氧化物纳米粒子 (NPs) 的植物合成已被广泛报道；然而，在合成的 NPs 中所涉及的机制和掺入的生物活性化合物仍有待研究。在这方面，这里已经开发了一种有效的可持续共沉淀合成氧化锌纳米粒子 (ZnO NPs)，采用水热反应，使用金莲花叶的有机化合物。通过X射线衍射鉴定纯六方纤锌矿ZnO，并通过场发射扫描电子显微镜观察尺寸范围为50-60nm的NP。X 射线光电子能谱揭示了与结合的金莲花生物活性化合物相关的官能团对 ZnO 的表面改性. 具有 3.29 eV 的非光学直接带隙和 2.85 eV 的光学带隙能量的植物功能化 ZnO NPs 通过循环伏安法在各种扫描速率、电流密度范围内的恒电流充放电和电化学阻抗谱（Z' vs .Z” 和 Z 与频率）在含水电解质中。制造的 ZnO 基电极在 2 mV/s 时的比电容为 86.5 F/g，2000 次循环的库仑效率为 97%。1.04Ω的较低内阻证明了良好的电化学导电性。因此，本研究表明有机化合物掺入 ZnO NPs 对超级电容器具有巨大的潜力。