Preparation of Cross-Linked Bimodal Mesoporous SBA-15 with Numerous Pore Openings

Abstract

Using poly (ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) as template and tetraethyl orthosilicate as silica source, well-ordered cross-linked bimodal mesoporous SBA-15 was easily prepared via an one-pot synthetic strategy, where a pre-self-assembly of P123 with TEOS in strong acidic media was introduced followed by pH-adjusting. The pH-adjusting can effectively change the copolymer micelle size, which directly lead to the formation of the bimodal mesoporous structure at pH range of 6-7.5, with most typical value at pH = 7.5. Meanwhile, these bimodal mesopores are interconnected, which generates a 3D intra-particle porosity with many pore-openings on the surfaces of particles. After modified with tetraethylenepentamine, the as-synthesized bimodal mesoporous SBA-15 exhibited the CO2 adsorption capacities much higher than as-synthesized conventional SBA-15. These bimodal mesoporous SBA-15 materials have great potential application in CO2 capture.