Sharbatdaran Masoomeh, Janbazi Mehdi
Physics and Accelerators School, Nuclear Sciences and Technology Research Institute Karaj Iran
RSC Adv. 2024 Sep 30;14(42):31153-31164. doi: 10.1039/d4ra04252b. eCollection 2024 Sep 24.
Zinc oxide nanoparticles were synthesized using sol-gel and hydrothermal techniques and characterized at different calcination temperatures (400, 500, and 600 °C). The study included an analysis of morphology, crystalline phase, particle size, elemental analysis, specific surface area and chemical state. Various characterization methods were employed, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), surface analysis (BET), nitrogen absorption and desorption (N-desorption), Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA-DSC), temperature-programmed reduction of hydrogen (H-TPR). Additionally, magnetic properties ZnO nanoparticles were investigated by electron spin resonance (ESR). The investigation revealed changes in reduction behavior, electron spin states, and magnetic properties. The interplay between defects, crystallization, and stability underscores the complexity of ZnO-NPs. These findings contribute to our understanding of nanomaterials and their potential applications in various fields. Density Functional Theory (DFT) calculations with a Hubbard U correction were performed to investigate native defects in ZnO and ZnOCH structures under oxygen-poor (low temperature), oxygen-rich (high temperature) and equilibrium (average temperature) conditions. The formation energies of native defects were calculated, and ESR spectra were simulated to analyze the presence and absence of C[double bond, length as m-dash]O, C-O, CH, and OH bands, as well as to identify the native defects present during growth. The results of the formation energy calculations and the simulated ESR spectra showed that the growth environment influences the native defects that occur during the ZnO preparation process. Inconsistencies between the calculation of formation energy and the ESR spectra suggested that the C[double bond, length as m-dash]O, C-O, CH, and OH bands were negligible and could be disregarded in the ZnO nanoparticles. The findings from this study contribute to a deeper understanding of ZnO-NPs, enabling the optimization of their properties for specific applications, such as effective catalysts in chemical reactions.
采用溶胶 - 凝胶法和水热法合成了氧化锌纳米颗粒，并在不同煅烧温度（400、500和600℃）下对其进行了表征。该研究包括对形态、晶相、粒径、元素分析、比表面积和化学状态的分析。采用了各种表征方法，包括扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线粉末衍射（XRD）、表面分析（BET）、氮吸附和解吸（N - 解吸）、傅里叶变换红外光谱（FTIR）、热分析（TGA - DSC）、程序升温氢气还原（H - TPR）。此外，通过电子自旋共振（ESR）研究了氧化锌纳米颗粒的磁性。研究揭示了还原行为、电子自旋态和磁性的变化。缺陷、结晶和稳定性之间的相互作用突出了氧化锌纳米颗粒的复杂性。这些发现有助于我们理解纳米材料及其在各个领域的潜在应用。进行了带有哈伯德U校正的密度泛函理论（DFT）计算，以研究在贫氧（低温）、富氧（高温）和平衡（平均温度）条件下氧化锌和氧化锌碳结构中的本征缺陷。计算了本征缺陷的形成能，并模拟了ESR光谱，以分析C = O、C - O、CH和OH带的存在与否，以及识别生长过程中存在的本征缺陷。形成能计算结果和模拟的ESR光谱表明，生长环境会影响氧化锌制备过程中出现的本征缺陷。形成能计算与ESR光谱之间的不一致表明，在氧化锌纳米颗粒中，C = O、C - O、CH和OH带可忽略不计。本研究的结果有助于更深入地理解氧化锌纳米颗粒，从而能够针对特定应用优化其性能，例如化学反应中的有效催化剂。
