Abstract

A new method was proposed to synthesize aerogels based on Al₂O₃–TiO₂ by the hydrolysis of mixed solutions of titanium tetrachloride and aluminum nitrate in the presence of propylene oxide, followed by supercritical drying of the obtained gels. The aerogels are characterized by a high specific surface area (140–500 m²/g) and a high specific porosity (1.7–2.7 cm³/g). Heat treatment of the Al₂O₃–TiO₂ aerogels at temperatures up to 600°C does not lead to crystallization of titanium dioxide, whereas the formation of crystalline anatase in aerogels based on individual TiO₂ is observed already at a temperature of 450°C. Using the standardized ISO 24443-2016 method, the SPF value of the obtained materials was determined, which turned out to be comparable to the characteristics of a commercial inorganic UV filter based on TiO₂ (Kronos 1171). At the same time, the photocatalytic activity of the Al₂O₃–TiO₂ aerogels turned out to be more than 120 times lower than the similar characteristics of the commercial UV filter based on titanium dioxide. The results obtained demonstrated that the Al₂O₃–TiO₂ aerogels are promising as components of sunscreens.

中文翻译：

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环氧化物介导的双组分 Al2O3-TiO2 气凝胶的合成及其防紫外线特性

摘要

提出了一种合成Al ₂ O ₃ -TiO ₂气凝胶的新方法，即四氯化钛和硝酸铝的混合溶液在环氧丙烷存在下水解，然后对所得凝胶进行超临界干燥。气凝胶的特点是高比表面积（140-500 m ² /g）和高比孔隙率（1.7-2.7 cm ³ /g）。_{Al 2} O ₃ –TiO ₂气凝胶在高达 600°C 的温度下进行热处理不会导致二氧化钛结晶，而在 450°C 的温度下已经观察到基于单独 TiO ₂的气凝胶中结晶锐钛矿的形成C。_{使用标准化 ISO 24443-2016 方法测定了所得材料的 SPF 值，结果证明其与基于 TiO 2}的商用无机紫外线过滤剂 (Kronos 1171) 的特性相当。同时，Al ₂ O ₃ -TiO ₂气凝胶的光催化活性比基于二氧化钛的商用紫外线过滤剂的类似特性低120倍以上。所得结果表明Al ₂ O ₃ -TiO ₂气凝胶作为防晒霜的成分很有前景。