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

Abstract

Li4SiO4 has been evaluated as one of the most promising CO2 absorbers to mitigate climate changes caused by excessive CO2 emissions. Li4SiO4 absorbents with a high specific surface area would hold higher CO2 capture capacity. However, with the lack of suitable SiO2 precursors, the synthesis of Li4SiO4 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 m2/g), and a large pore volume 0.86∼1.23 cm3/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 Li4SiO4 microspheres, which enhanced CO2 adsorption.