Investigations on 2LiH+MgB2+LixTiO2 composite as hydrogen purification system under CO containing atmosphere

N. GAMBA; J. PUSZKIEL; G. AMICA; P. ARNEODO LAROCHETTE; F. C. GENNARI

Río de Janeiro

Conferencia; WHEC 2018 (World Hydrogen Energy Conference); 2018

International Association for Hydrogen Energy (IAHE)

Lithium reactive hydride composite, i.e. 2LiH+MgB2 or 2LiBH4+MgH2 stoichiometric hydride mixture, presents potential characteristics for practical hydrogen storage applications. Puszkiel et al. have reported a notable improvement on the hydrogen storage properties of 2LiH+MgB2 reactive hydride composite by the addition of TiO2. The presence of TiO2 leads to the in-situ formation of core-shell LixTiO2 nanoparticles, which act as reversible Li+ source/sink upon hydrogenation and dehydrogenation. Nowadays, hydrogen storage and hydrogen consuming applications usually require the use of high purity hydrogen. Therefore, being motivated by the improved hydrogen storage properties of the TiO2 doped 2LiH+MgB2 hydride composite, it has been evaluated as hydrogen purification system under CO containing atmosphere. In this work, the hydrogen absorption-desorption kinetic behavior as well as the thermodynamic properties of the TiO2 doped 2LiH-MgB2 composite after repetitive dehydrogenation and rehydrogenation cycles with 0.1 mol% of CO-H2 mixture have been investigated via the volumetric technique in a modified Sieverts apparatus. Structural information of samples after cycling has been obtained by Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). Experimental results do not indicate any clear interaction between CO and 2LiH+MgB2+TiO2 composite. Moreover, the effect of CO on 2LiH+MgB2+TiO2 composite is not evident during cycling because neither the hydrogen storage capacity of the system nor the hydrogen desorption rate are affected. In order to shed light on the interaction between CO and the composite, specific experiments have been designed with pure CO. A reactivity ranking of the different components of the composite with CO has been established.