The catalytic reactions in the Cu-Li-Mg-H high capacity hydrogen storage system

• Tipo: Artigo em Revista Científica Internacional
• Data: 2014

Autores

Helena Braga (Autor) FEUP; Anter El-Azab (Autor) Outra

Revista

Título: Physical Chemistry Chemical Physics

Vol. 16

Páginas: 23012-23025

ISSN: 1463-9076

Editora: Royal Society of Chemistry

Indexação

ISI Web of Knowledge - 7 Citações

ISI Web of Science

Scopus - 8 Citações

Classificação Científica

FOS: Ciências exactas e naturais

Outras Informações

ID Authenticus: P-009-WHD

DOI: 10.1039/c4cp01815j

Abstract (EN): A family of hydrides, including the high capacity MgH2 and LiH, is reported. The disadvantages these hydrides normally display (high absorption/desorption temperatures and poor kinetics) are mitigated by Cu-hydride catalysis. This paper reports on the synthesis of novel CuLi0.08Mg1.42H4 and CuLi0.08Mg1.92H5 hydrides, which are structurally and thermodynamically characterized for the first time. The CuLi0.08Mg1.42H4 hydride structure in nanotubes is able to hold molecular H-2, increasing the gravimetric and volumetric capacity of this compound. The catalytic effect these compounds show on hydride formation and decomposition of CuMg2 and Cu2Mg/MgH2, Li and LiH, Mg and MgH2 is analyzed. The Gibbs energy, decomposition temperature, and gravimetric capacity of the reactions occurring within the Cu-Li-Mg-H system are presented for the first time. First principles and phonon calculations are compared with experiments, including neutron spectroscopy. It is demonstrated that the most advantageous sample contains CuLi0.08Mg1.92 and (Li) similar to Li2Mg3; it desorbs/absorbs hydrogen according to the reaction, 2CuLi(0.08)Mg(1.42)H(4) + 2Li + 4MgH(2) <-> 2CuLi(0.08)Mg(1.92) + Li2Mg3 + 8H(2) at 114 degrees C (5.0 wt%) - 1 atm, falling within the proton exchange membrane fuel cell applications window. Finally the reaction 2CuLi(0.08)Mg(1.42)H(4) + MgH2 <-> 2CuLi(0.08)Mg(1.92) + 5H(2) at 15 degrees C (4.4 wt%) - 1 atm is found to be the main reaction of the samples containing CuLi0.08Mg1.92 that were analyzed in this study.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 14