Kinetic and thermodynamic research of hydrogen absorption by CoZr and NiZr alloys

Density Functional Theory-Based Kinetic Modeling of Reactions of Hydrogen Isotopes (H2, D2, T2) and Carbonaceous Gases (CO2, CO, CH4) on the ZrCo(110) Surface

“…In addition, many experiments on the pressure composition isotherm characterizations usually expose the ZrCo alloy in hydrogen gas for hours to fully reach equilibrium and the required adsorption time continues to increase with lower hydrogen pressures. , Kinetic results for H 2 (D 2 , T 2 ) + CO 2 reactions indicate that ZrCo could be immune to CO 2 -poisoning for a relatively long hydrogen resident time to reach saturated hydrogen storage capacity before being poisoned at room temperature. On the other hand, the practical poisoning effect of impurity gas on ZrCo could be more pronounced because experiments normally utilized powder samples, ,, whose molecular adsorption/desorption kinetics are much faster due to higher ratio surface area and possible surface defects. In addition, as shown from experiments , as well as our simulation results above, theadsorption rate of D 2 (T 2 ) is generally slower than H 2 , which would call for longer reaction time to reach certain D 2 (T 2 )-storage capacity for ZrCo and thus make it more likely to react with gaseous contaminants.…”

The Statistical-Thermodynamic Theory of P—c—T-Dependences for Zirconium—Nickel Alloy Trihydride ZrNiH$_{3}$

“…The crystal lattice of the CrB type. The parallel-displaced layers are shown with formation of zigzag chains along the z-axis by the chromium and boron atoms [61]. parallel layers in the planes (x, y), which are shifted relative to each other in these planes.…”

“…The heating of the sample at temperature of  300C initiates a desorption process. Figure 4 shows the graphic data of the differential thermal analysis (DTA), differential scanning calorimetry (DSC) and temperature gravimetry (TG) [61][62][63][64][65][66]. According to the paper [65], the reducing of the heat flow (endothermic peak at 264C) during hydrogenation is caused by phase transition in a system of hydrogen atoms because of their distribution (ordering) on their positions with forming in the beginning the ZrNiH phase and then the ZrNiH 3 one.…”

“…Experimental plots[61][62][63][64][65][66]: DTA plot of hydrogen sorption in the ZrNi-H 2 system. Endopeak is at the hydrogen absorption; exopeak is at the hydrogen extraction (a); DSC graph-the heat flow at the dehydrogenation of ZrNiH 3 (peak 1) and at the hydrogenation of ZrNi (peak 2) as a result of heating in the regime of 5 K/min (b); DSC plot-the heat flow at the hydrogen yield from the ZrNiH 3 alloy at the heating rate of 5 K/min (c); TG curve-the mass loss of the ZrNiH 3 specimen at the hydrogen desorption (d).…”