This present study was carried out to synthesize cobalt-doped and undoped titanium dioxide nanosized particles using sonochemical hydrolysis technique. The microstructure and morphological characteristics of the synthesized samples have been studied using X-ray diffractometer and high-resolution transmission electron microscope, respectively. The obtained results of characterization have confirmed the amorphous nature of the undoped sample. However, cobalt-doped titanium dioxide samples are in anatase phase. The obtained phase structure proposed the effect of acidity level during the hydrolysis process at relatively low temperature. Anatase phase is the predominant phase for the doped samples with small traces of brookite phase depending on the concentration of cobalt nitrate as the precursor salt in the hydrolysis process. The estimated crystallite sizes of the doped samples are ranging from 6.1 nm to 6.8 nm. The diffuse reflectance measurement revealed high near-infrared solar reflectance (R*), 85.3%, for amorphous nanosized titanium dioxide which is a white (non-coloured) sample. Moreover, cobalt-doped titanium dioxide, coloured samples, showed reasonable high values of R* with respect to their coloured feature and were found to be 53% and 51% for the synthesized samples at molecular weight percentage ratios between cobalt and titanium precursors; 5% and 10%, respectively.

中文翻译：

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通过简便的声化学水解技术制备的钴掺杂二氧化钛纳米结构粉末的结构和漫反射特性

本研究旨在使用声化学水解技术合成钴掺杂和未掺杂的二氧化钛纳米颗粒。分别使用X射线衍射仪和高分辨率透射电子显微镜研究了合成样品的微观结构和形态特征。获得的表征结果证实了未掺杂样品的非晶性质。然而，钴掺杂的二氧化钛样品处于锐钛矿相。获得的相结构表明了在较低温度下水解过程中酸度水平的影响。锐钛矿相是掺杂样品的主要相，其中含有少量板钛矿相，具体取决于水解过程中作为前体盐的硝酸钴的浓度。掺杂样品的估计微晶尺寸范围为 6.1 nm 至 6.8 nm。漫反射测量显示，白色（无色）样品的无定形纳米二氧化钛的近红外太阳反射率 (R*) 高达 85.3%。此外，掺杂钴的二氧化钛（有色样品）在其有色特征方面显示出合理的高 R* 值，并且发现合成样品在钴和钛前体之间的分子量百分比下分别为 53% 和 51%；分别为 5% 和 10%。有色样品，在其颜色特征方面显示出合理的高 R* 值，并且发现合成样品在钴和钛前体之间的分子量百分比下分别为 53% 和 51%；分别为 5% 和 10%。有色样品，在其颜色特征方面显示出合理的高 R* 值，并且发现合成样品在钴和钛前体之间的分子量百分比下分别为 53% 和 51%；分别为 5% 和 10%。