The very wide applications of LTA zeolites,e.g.tritiated water storage,imply that a precise atomic-scale description of the adsorption processes taking place in their structure is crucial.The zeolite structure seems t...The very wide applications of LTA zeolites,e.g.tritiated water storage,imply that a precise atomic-scale description of the adsorption processes taking place in their structure is crucial.The zeolite structure seems to have a catalytic effect on the O_(2)/H_(2)recombination during the storage process after water radiolysis.To look closely at the conditions that could bring O_(2)and H_(2)to this particular point,we have conducted investigations using static DFT and systematic ab initio molecular dynamics calculations.We have investigated the interaction of these two molecules with the sodium cations,on which the adsorption capacity of the Na-LTA zeolite depends.The O_(2)and H_(2)molecules’behaviour inside the cavities is linked to the Na+position and availability.The latter is regulated by the presence of H_(2)O which interacts with Na+in a stronger way than O_(2)and H_(2).Thus,the adsorption studies of different mixtures(O_(2)/H_(2)O,H_(2)/H_(2)O and H_(2)/O_(2))have been carried out to characterise the competition between water and other vip molecules.The absence of an obvious interaction between the adsorbates strongly suggests a potential reaction path involving the catalytic effect of the zeolite.Since we have been able to show that the behaviour of O_(2)and H_(2)molecules is directly affected by the water coverage rate,the reaction path is very likely to be affected too.These results mark a step towards the description of a recombination mechanism between O_(2)and H_(2)in a zeolite structure,a crucial issue for such systems involving tritiated water adsorbed in nanoporous materials.展开更多
基金the Mésocentre de calcul de Franche-Comte and on the TGCC(Très Grand Centre de Calcul du CEA)the HPC resources of TGCC under the allocations 2019-A0060910785 and 2020-A0080910785 provided by GENCI.
文摘The very wide applications of LTA zeolites,e.g.tritiated water storage,imply that a precise atomic-scale description of the adsorption processes taking place in their structure is crucial.The zeolite structure seems to have a catalytic effect on the O_(2)/H_(2)recombination during the storage process after water radiolysis.To look closely at the conditions that could bring O_(2)and H_(2)to this particular point,we have conducted investigations using static DFT and systematic ab initio molecular dynamics calculations.We have investigated the interaction of these two molecules with the sodium cations,on which the adsorption capacity of the Na-LTA zeolite depends.The O_(2)and H_(2)molecules’behaviour inside the cavities is linked to the Na+position and availability.The latter is regulated by the presence of H_(2)O which interacts with Na+in a stronger way than O_(2)and H_(2).Thus,the adsorption studies of different mixtures(O_(2)/H_(2)O,H_(2)/H_(2)O and H_(2)/O_(2))have been carried out to characterise the competition between water and other vip molecules.The absence of an obvious interaction between the adsorbates strongly suggests a potential reaction path involving the catalytic effect of the zeolite.Since we have been able to show that the behaviour of O_(2)and H_(2)molecules is directly affected by the water coverage rate,the reaction path is very likely to be affected too.These results mark a step towards the description of a recombination mechanism between O_(2)and H_(2)in a zeolite structure,a crucial issue for such systems involving tritiated water adsorbed in nanoporous materials.
