Investigation of grafted mesoporous silicon sponge using hyperpolarized 129 Xe NMR spectroscopy

• Published in: Journal of materials research Vol. 33; no. 17; pp. 2637 - 2645
• Main Authors: Mao, Yougang, Kim, Dokyoung, Hopson, Russell, Sailor, Michael J., Wang, Li-Qiong
• Format: Journal Article
• Language: English
• Published: United States Materials Research Society 14.09.2018
• Subjects: Materials Science
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2018.226

Abstract Temperature-dependent (173–373 K) hyperpolarized 129 Xe nuclear magnetic resonance ( 129 Xe NMR) analyses along with transmission electron microscopy and N 2 adsorption measurements have been applied to understand pore structure and interconnectivity of bare and grafted mesoporous silicon sponge (MSS) materials. The Xe NMR chemical shift data indicate the existence of micropores inside the larger mesopore channels and the effects of grafting on the pore surfaces. The grafted layer estimated at 2 nm in thickness blocks the micropores on the surfaces of mesoporous channels. Partitioning of Xe between the micropores and the mesopores in the MSS materials is temperature-dependent, with Xe principally occupying the micropores at lower temperatures. In addition, the temperature-dependent Xe peak shift of MSS materials verifies the increased uniformity and interconnectivity of mesopores after surface grafting. The results from this study provide useful information for design and development of novel materials.