In this work, we developed a new method to synthesize silica aerogel microspheres via ambient pressure drying (APD) process without applying any surfactants and mechanical stirring. An ethanol solution of partially hydrolyzed, partially condensed silica (CS) was used as precursor in the synthesis, the water-repellent n-Heptane as solvent, while the water-soluble ammonia gas (NH₃) as catalyst. After a fast sol-gel process and APD process, aerogel microspheres were obtained in the form of white powder with packing density ranged from 62 mg/cm³ to 230 mg/cm³ for different samples. The SEM images exhibited fine spherical morphology for these aerogel microparticles, and their statistical average particle diameter ranged from 0.8 μm to 1.5 μm. Besides, according to the analysis of N₂ adsorption-desorption isotherms, the BET surface area of these aerogel microspheres was in the range of 800–960 m²/g, and a considerable volume of micropores was detected along with the abundant mesospores in these microspheres, which was further confirmed by the TEM image and SAXS curve. Based on the very limited solubility of NH₃ in the reaction system, a non-emulsion formation mechanism was proposed to illustrate the formation of these aerogel microspheres.

在这项工作中，我们开发了一种通过环境压力干燥（APD）工艺合成二氧化硅气凝胶微球的新方法，而无需施加任何表面活性剂和机械搅拌。合成中使用部分水解，部分缩合的二氧化硅（CS）的乙醇溶液作为前体，以疏水正庚烷为溶剂，而水溶性氨气（NH ₃）为催化剂。经过快速的溶胶-凝胶工艺和APD工艺，获得了白色粉末形式的气凝胶微球，堆积密度为62 mg / cm ³至230 mg / cm ^3。对于不同的样品。SEM图像显示出这些气凝胶微粒的精细球形形态，并且它们的统计平均粒径在0.8μm至1.5μm的范围内。此外，根据N ₂吸附-解吸等温线的分析，这些气凝胶微球的BET表面积在800-960 m ² / g的范围内，并且在其中检测到大量的微孔以及大量的中孔微球，这进一步由TEM图像和SAXS曲线证实。基于NH ₃在反应体系中的溶解度非常有限，提出了一种非乳液形成机理来说明这些气凝胶微球的形成。