Confined Jet Impingement Continuous Microchannel Reactor Synthesis of Ultrahigh-Quality Mesoporous Silica Nanospheres for CO₂ Capture

Abstract

Li 4 SiO 4 has been evaluated as one of the most promising CO 2 absorbers to mitigate climate changes caused by excessive CO 2 emissions. Li 4 SiO 4 absorbents with a high specific surface area would hold higher CO 2 capture capacity. However, with the lack of suitable SiO 2 precursors, the synthesis of Li 4 SiO 4 absorbents with a high specific surface area and a well-defined hollow sphere structure was still challenging. Here, a two-stream confined jet impingement continuous microchannel reactor was proposed to produce ultrahigh-quality mesoporous silica nanospheres (UHMSNs) with an ultrahigh specific surface area and a small particle size. The obtained UHMSNs possessed excellent water dispersibility, a uniform diameter (142−207 nm), tunable perpendicular mesopores (2.6−3.3 nm), a high surface area (1347∼1854 m 2 /g), and a large pore volume 0.86∼1.23 cm 3 /g). Moreover, MesoDyn simulation provided valuable information to optimize the nucleation stage and the crystallization stage of UHMSNs. Additionally, UHMSNs were used as the silicon source to synthesize the petal-like hollow structure of Li 4 SiO 4 microspheres, which enhanced CO 2 adsorption.