CO 2 Capture by Na 2 TeO 4 : Structure of Na 2- x H x TeO 4 and Kinetic Aspects

• Published in: Inorganic chemistry 2019-07, Vol.58 (13), p.8866-8876
• Main Authors: Galven, Cyrille, Pagnier, Thierry, Dittmer, Jens, Le Berre, Françoise, Crosnier-Lopez, Marie-Pierre
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b01282

β-Na TeO is able to trap CO in a humid atmosphere due to a partial Na /H exchange and the formation of NaHCO . The RT powder X-ray diffraction pattern of the resulting Na H TeO shows broad and narrow hkl lines preventing the structural study. We show by the DIFFaX program that Na /H exchange is topotactic since the structure, as in the mother form, consists of [TeO ] chains of TeO octahedra. We also show that the broadening of some hkl lines is due to stacking faults which result from the weakness of H-O···H bonds connecting the [TeO ] chains. Upon heating, a progressive structural organization takes place which has been followed by powder X-ray diffraction, Raman, and NMR spectroscopies. Around 300 °C, a well organized structure can be described from powder X-ray diffraction refinements in the monoclinic P2 / n space group while ab initio computations allowed location of the hydrogen atoms with satisfactory H-O bonds. In addition, we present the CO sorption/desorption by Na TeO and compare its performance to that of Na SiO . Finally, the existence of a Na Li TeO solid solution (0 ≤ x ≤ 0.9) is evidenced, and we show that the presence of lithium in the structure leads to the disappearance of the structural transition observed for β-Na TeO and to a progressive decrease of the CO capture ability.