Low barriers for hydrogen diffusion in sII clathrate

Journal article (2015)

Authors

T.T. Trinh Norwegian University of Science and Technology (NTNU)
Magnus H. Waage Norwegian University of Science and Technology (NTNU)
Titus S. Van Erp Norwegian University of Science and Technology (NTNU)
S.H. Bedeaux Engineering Thermodynamics - Mechanical, Maritime and Materials Engineering , Norwegian University of Science and Technology (NTNU)
Research Group
Engineering Thermodynamics (Mechanical, Maritime and Materials Engineering) (TU Delft)
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Published Date

2015

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Process and Energy

Research Group

Engineering Thermodynamics

Abstract

The transport of gas molecules in hydrates is presently poorly understood. In sII structured hydrates with hydrogen guests there is, for instance, a mismatch between experimental and computed values for diffusion constants. We provide an explanation for the experimentally observed diffusion rates, using DFT-based molecular dynamics simulations at 100 K. By considering the effect of cage occupancy, as well as the flexibility of the water lattice, we show that barriers for hydrogen diffusing between cages, can approach values as low as 5 kJ mol-1, which is very close to experimental values.