Enhanced Hydrogen-Storage Capacity and Structural Stability of an Organic Clathrate Structure with Fullerene (C₆₀) Guests and Lithium Doping

Abstract

An effective combination of host and guest molecules in a framework type of architecture can enhance the structural stability and physical properties of clathrate compounds. We report here that an organic clathrate compound consisting of a fullerene (C60) guest and a hydroquinone (HQ) host framework shows enhanced hydrogen-storage capacity and good structural stability under pressures and temperatures up to 10 GPa and 438 K, respectively. This combined structure is formed in the extended β-type HQ clathrate and admits 16 hydrogen molecules per cage, leading to a volumetric hydrogen uptake of 49.5 g L–1 at 77 K and 8 MPa, a value enhanced by 130% compared to that associated with the β-type HQ clathrate. A close examination according to density functional theory calculations and grand canonical Monte Carlo simulations confirms the synergistic combination effect of the guest–host molecules tailored for enhanced hydrogen storage. Moreover, the model simulations demonstrate that the lithium-doped HQ clathrates with C60 guests reveal exceptionally high hydrogen-storage capacities. These results provide a new playground for additional fundamental studies of the structure–property relationships and migration characteristics of small molecules in nanostructured materials.

Simulation of Capture and Release Processes of Hydrogen by β-Hydroquinone Clathrate

“…13−16 The HQ clathrate with C60 as the guest was recently proposed for H 2 enhanced storage. 17 Lee et al have investigated the controlled separation of gas mixtures using clathrates, 18−22 finding a remarkable selectivity of the HQ clathrate for CO 2 molecules. This fact suggests the application of HQ clathrates as CO 2 scrubbers 23 for decarbonization-related processes.…”

“…Nevertheless, the main reason supporting ongoing studies of HQ clathrates is their potential use as selective containers for substances of industrial or strategic interest. For example, the HQ clathrate could be used as a solid source of radioactive materials or for H 2 storage. − The HQ clathrate with C60 as the guest was recently proposed for H 2 enhanced storage . Lee et al have investigated the controlled separation of gas mixtures using clathrates, − finding a remarkable selectivity of the HQ clathrate for CO 2 molecules.…”

Li–fluorine codoped electrospun carbon nanofibers for enhanced hydrogen storage

“…17,18 However, a series of carbon-based materials (such as carbon bers, graphene and carbon nanotubes) show a moderate performance, [19][20][21][22][23] which is attributed to the weak physisorption between molecular hydrogen and carbon-based materials. [24][25][26] To increase the physisorption-based storage capability, large surface areas, 27,28 heteroatom doping [29][30][31][32][33][34] and alkali metal loading [35][36][37][38] of carbon-based materials are highly desired. High specic surface areas and appropriate pore sizes signicantly improve hydrogen molecule adsorption, which could be ful-lled by nanoporous carbon structures.…”

“…To increase the physisorption-based storage capability, large surface areas, 27,28 heteroatom doping 29–34 and alkali metal loading 35–38 of carbon-based materials are highly desired. High specific surface areas and appropriate pore sizes significantly improve hydrogen molecule adsorption, which could be fulfilled by nanoporous carbon structures.…”

Obtaining of hydroxylated fullerenes Y@C82OX(OH)Y, Y2@C82OX(OH)Y, Y2C2@C82OX(OH)Y and electrophysical characteristic of composite film based thereon

“…Common fullerenes, with molecules of empty framework, are applied in many fields of science and technology [1][2][3][4][5][6][7][8]. Endohedral metalfullerenes, substances molecules of which consist of the carbon atoms located on the quasispherical closed surface, containing one or several metal atoms, are of special interest.…”