Enhanced kinetics for CO₂ sorption in amine-functionalized mesoporous silica nanosphere with inverted cone-shaped pore structure

Amine-functionalized mesoporous silica is one of the most promising solid sorbents for CO₂ capture. The pore structure of sorbents plays a crucial role in enhancing sorption and desorption kinetics. In this work, mesoporous silica nanosphere (MSN) with inverted cone-shaped pore structure was synthesized and examined as the support for polyethyleneimine (PEI). The unique pore structure of MSN support for PEI resulted in significantly faster sorption and desorption rates and higher sorption capacity within short sorption time when compared to the benchmark support SBA-15 with the same amount of PEI loading. With 65 wt% PEI loading, 65PEI/MSN sorbent showed about 50% higher working capacity, together with 27% faster rate of CO₂ sorption and 71% faster rate of CO₂ desorption, compared to that with 65PEI/SBA-15 in sorption/desorption cycles. PEI/MSN sorbents have great potential for practical applications in CO₂ capture.