Storage of hydrogen in nano-confined hydrates

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Institute: Imperial College London
Closing date: 31 July 2022

Department of Chemical Engineering

About the Project

The student will be hosted in the Molecular Systems Engineering group[1] at Imperial College London.

Conditions

  • This project is a fully-funded CASE award supported by bp. 
  • It is ringfenced for UK (home) students
  • It is aimed at 1st class students ( Chem. Eng., Physics, Materials, Chemistry or similar) who have confidence in coding, and ideally some background in molecular simulations and machine learning.
  • Starting date: ASAP
  • Deadline: 31 July 2022 or until a suitable candidate is identified.

Aim of the research

This project will explore the feasibility of storing hydrogen in water clathrates stabilized within nanoporous materials. If successful, we envisage this technology to be a game-changing alternative to commonly suggested physical and chemical storage solutions, providing adequate storage in environmentally friendly environments and at modest conditions of temperature and pressure.

We will employ classical molecular simulation techniques to advance the knowledge of chemical relevance, applicability and viability of porous materials as hosts for hydrogen hydrates. 

Background

Hydrogen provides for a credible renewable energy vector. However, implementation of a hydrogen-based fuel economy has been limited by difficulties achieving efficient storage and transport[2]. Conventional physical-based hydrogen storage methods include liquefaction, which requires prohibitively low temperatures (20K), and compression which exhibits poor efficiency unless similarly prohibitive high pressures are used. To this end, significant attention has been dedicated to storage of hydrogen as an adsorbed fluid within solid-state materials (e.g. Metal-Organic Frameworks, nanoporous carbons, etc.), but none of these have been found to provide the required combination of high capacity with favourable thermodynamics and kinetics[3].

A further proposal is the storage under the form of hydrates (also known as hydrogen clathrates)[4]. Hydrates are crystalline solids in which hydrogen molecules are trapped in polyhedral water cages. These compounds provide energy densities comparable to compressed gas, as a consequence of the small inter-cage gas molecule spacing. Hydrates possess a number of unique favourable properties: they are low-cost, environmentally friendly, non-flammable and their formation is fully reversible. However, bulk phase hydrogen clathrates require high (>200MPa) pressures to form, making this an important limitation for processing. 

The formation of clathrates in nano-confined media has the potential to facilitate hydrate growth by dramatically increasing the water/gas interfacial area. Furthermore, confinement stabilises the resulting structures, allowing synthesis under mild conditions with fast kinetics[5]. To date there have been no reports published in the open literature on the storage of hydrogen in nano-confined hydrates and this is where this project is positioned. There is therefore a significant opportunity to computationally investigate these potentially game-changing materials.

Experimental determination of the process variables is challenging, not only because of the need to consider high pressure hydrogen equipment, but also because of the challenges to identify ( through spectroscopy, scattering, etc.) the presence of hydrates in confined media. In that sense, a computational screening will bracket the plausible phase space to be considered and the ultimate limits of the technology. Our group has close links with experimental groups that will feed in to the results at later stages in the project.

The project is computational in nature, employing classical molecular dynamics and available force fields. There is an opportunity to explore both coarse-grained models and machine-learning potentials.

The proposal is a blue-skies project, however, the potential of the technology is significant, as it would provide for a mechanism to store hydrogen in a low-cost, environmentally friendly, safe and fully reversible manner.

[1] https://www.molecularsystemsengineering.org

[2] L. Schlapbach and A. Züttel. Hydrogen-storage materials for mobile applications. Nature, 414(6861):353–358, 2001

[3] Chen, Z. et al. Balancing volumetric and gravimetric uptake in highly porous materials for clean energy. Science 368, 297–303 (2020).

[4] A. Gupta, et al. Hydrogen Clathrates: Next Generation Hydrogen Storage Materials. Energy Storage Materials, 41:69–107, 2021.

[5] N. N. Nguyen, M. Galib, and A. V. Nguyen. Critical Review on Gas Hydrate Formation at Solid Surfaces and in Confined Spaces: Why and How Does Interfacial Regime Matter? Energy & Fuels, 34(6):6751–6760, 2020

Deadline for applications: 31 July 2022