Continuous increases in atmospheric carbon dioxide (CO 2 ) concentration has led to significant climate and environmental concerns. CO 2 capture and thermal insulation are effective measures to reduce CO 2 emissions. Among these, aerogels exhibit remarkable performance in excellent performance in thermal insulation and CO 2 adsorption owing to their unique and tailorable porous structure and surface chemistry. Nonetheless, while methyl-functionalized aerogels for thermal insulation and amine-functionalized aerogels for CO 2 capture have been extensively developed, it remains challenging to integrate amine and methyl groups in a material stably owing to their quite different feature. This major limitation leads to an increase in cost and a reduction of flexibility in terms of manufacture and application.
To that end, in a study published in the KeAi journal Green Chemical Engineering , researchers from China described a new silica aerogel they have developed— bifunctionalized hybrid silica aerogels for stable low-concentration CO 2 capture and thermal insulation under humid and high-temperature conditions.
“Silica aerogel is like a machine with multiple interfaces. With the support of various functional components, of course, it can achieve multiple functions,”explains the study’s senior author, Xiaodong Shen, a professor in materials at Nanjing Tech University. “The structural characteristics of silica aerogels, such as high porosity and specific surface area, endow them with high thermal resistance and gas adsorption capacity. Interestingly, the surface groups of silica aerogels can be tailored by specific precursors, enabling them to possess specific functions. These features provide conditions for the synthesis of multifunctional silica aerogels.”
The team discovered that the integration of amine and methyl groups in a silica aerogel was completed readily by a facile and environmentally friendly self-catalyzed sol-gel reaction with co-condensation of multicomponent precursor involved. This not only enhanced the stability of functional groups under high temperatures, but also avoided the blockage of pore space under traditional synthesis route of aerogels.
“High specific surface area, porosity, and surface amine loading were achieved by tailoring pore structure via precursor composition,” shares Shen. “This made the silica aerogel possess superior low-concentration CO 2 adsorption performance under humid conditions and excellent thermal insulation performance in a wide temperature range (-100-1300 ℃).”
According to lead author Yong Kong, the direct integration of two functional groups within silica aerogels has rarely been reported. “Our novel approach indicates that the hybridization of multiple functional groups in a silica aerogel can be achieved facilely by choosing applicable precursors,” says Kong. “We hope that our findings will encourage scientists to continue developing novel aerogels by new processes to promote the applications of aerogels in carbon neutral.”
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Contact the author: Yong Kong, College of Materials Science and Engineering, Nanjing Tech University, ykong@njtech.edu.cn.
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Green Chemical Engineering
Experimental study
Not applicable
Bifunctionalized hybrid silica aerogels for stable low-concentration CO2 capture and thermal insulation under humid and high-temperature conditions
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.