Jensen, Peter Bjerre

Lysgaard, Steen

Quaade, Ulrich J.

Vegge, Tejs

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 18, 2017Designing New Materials for Ammonia Storage Using Density Functional Theory andGenetic AlgorithmsJensen, Peter Bjerre; Lysgaard, Steen; Quaade, Ulrich J.; Vegge, TejsPublication date:2014Link back to DTU OrbitCitation (APA):Jensen, P. B., Lysgaard, S., Quaade, U. J., & Vegge, T. (2014). Designing New Materials for Ammonia StorageUsing Density Functional Theory and Genetic Algorithms. Abstract from International Discussion on HydrogenEnergy and Applications, Nantes, France.IDHEA – May 12th-14th 2014 – Nantes, France    Designing New Materials for Ammonia Storage Using Density Functional Theory and Genetic Algorithms.  P.B. Jensen 1, S. Lysgaard 1, U. Quaade 2, T. Vegge 1  1DTU Energy Conversion - Kgs. Lyngby (Denmark) 2Amminex Emmissions Technology - Søborg (Denmark)     ABSTRACT:  Metal halide ammines, e.g. Mg(NH3)6Cl2 [1]⁠ and Sr(NH3)8Cl2 [2]⁠, can reversibly store ammonia, with high volumetric hydrogen storage capacities. The storage in the halide ammines is very safe, and the salts are therefore highly relevant as a carbon-free energy carrier in future transportation infrastructure. The so far known compounds, are not optimal because they release the ammonia in several steps and generally at too high temperatures. In this project we are searching for improved mixed materials with optimal desorption temperatures and kinetics, optimally releasing all ammonia below 100 °C in as few steps as possible. The stored energy can be released by using fuel cells, which can either be run directly on ammonia in a high temperature SOFC, in a direct ammonia fuel cell (DAFM) operating at intermediate temperatures, or be decomposed, and the hydrogen can be used in a low temperature PEMFC, which is a much more mature technology [3].  We apply Density Functional Theory, DFT, calculations on mixed compounds selected by a Genetic Algorithm (GA) [4]⁠, relying on biological principles of natural selection. The GA is evolving from an initial (random) population and selecting those with highest fitness, a function based on e.g. stability, release temperature, storage capacity and the price of the elements. The search space includes all alkaline earth, 3d and 4d metals in combination with chloride, bromide or iodide, and mixtures thereof. In total the search space consists of millions of combinations, which makes a GA ideal, to reduce the number of necessary calculations. We are screening for release from either a hexa or octa ammine, and we have found promising candidates, which will be further investigated – both computationally and experimentally.  References : [1] Sørensen RZ, Hummelshøj JS, Klerke A, Reves JB, Vegge T, Nørskov JK, et al. Indirect, reversible high-density hydrogen storage in compact metal ammine salts. J Am Chem Soc 2008;130:8660–8. [2] Lysgaard S, Ammitzbøll AL, Johnsen RE, Norby P, Quaade UJ, Vegge T. Resolving the stability and structure of strontium chloride amines from equilibrium pressures, XRD and DFT. Int J Hydrogen Energy 2012;37:18927–36. [3] Klerke A, Christensen CH, Nørskov JK, Vegge T. Ammonia for hydrogen storage: challenges and opportunities. J Mater Chem 2008;18:2304–10. [4] Lysgaard S, Landis DD, Bligaard T, Vegge T. Genetic Algorithm Procreation Operators for Alloy Nanoparticle Catalysts. Top Catal 2013. DOI:10.1007/s11244-013-0160-9   KEYWORDS: Indirect Hydrogen Storage - Ammonia Storage - Metal Halide Ammines  Density Functional Theory - Genetic Algorithms.   

Designing New Materials for Ammonia Storage Using Density Functional Theory and Genetic Algorithms

http://orbit.dtu.dk/ws/files/92383409/Designing_New_Materials.pdf

Designing New Materials for Ammonia Storage Using Density Functional Theory and Genetic Algorithms

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology