Mass Production of Multishell Hollow SiO2 Spheres With Adjustable Void Ratios and Pore Structures

Abstract SiO 2 multishell hollow spheres (MHSs) as supports have multiple porous layers and internal voids, which present notable advantages in regulating mass transport and chemical reactions. However, practical applications of SiO 2 MHSs are severely hindered because of their high costs and low production efficiency issues. Herein, it is overcome these obstacles by developing a precursor hydrolysis method and demonstrate a cost‐effective production of void‐ratio tunable SiO 2 MHSs on a large scale, which has a much lower cavitation temperature (25 °C) and one order of magnitude decrease in cost. In addition, the new method can also be applied to fabricate TiO 2 and SnO 2 hollow spheres (HSs). In particular, an NH 4 Cl precipitation‐pyrolysis strategy is developed to tune the pore diameters and pore distributions of SiO 2 MHSs with different void ratios. SiO 2 MHSs with varying void ratios and pore distributions have the broadest controlling release time ranges (30–430 h). The precursor hydrolysis method and NH 4 Cl precipitation‐pyrolysis strategy offer adequate stimulus to push forward SiO 2 MHSs from laboratory‐scale to industry‐scale applications.