Abstract
This paper reports the synthesis, structure, and hydrogen adsorption property of Li-doped mesoporous silica (MPS) with a 2D hexagonal structure. The Li-doping is achieved by impregnation of the cylindrical mesopores with an ethanol solution of lithium chloride followed by heat treatment. Detailed characterization by solid-state NMR, TG-MS, and FT-IR suggests that, during the heat treatment, lithium chloride reacts with surface ethoxy groups Si-OEt) to form =SiOLi groups, while ethyl chloride is released into the gas phase. The hydrogen uptake at 77 K and 1 atm increases from 0.68 wt% for the undoped MPS to 0.81 wt% for Li-doped MPS (Li-MPS). The isosteric heat of adsorption is 4.8 kJ∈mol-1, which is consistent with the quantum chemistry calculation result (5.12 kJ∈mol-1). The specific hydrogen adsorption on Li-MPS would be explained by the frontier orbital interaction between HOMO of hydrogen molecules and LUMO of = These findings provide an important insight into the development of hydrogen storage materials with specific adsorption sites.
Original language | English |
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Pages (from-to) | 211-218 |
Number of pages | 8 |
Journal | Adsorption |
Volume | 17 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 Feb 1 |
Externally published | Yes |
Keywords
- Hydrogen adsorption
- Li doping
- Mesoporous silica
- Quantum chemistry calculation
ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
- Surfaces and Interfaces