Probing room-temperature reactivity of H2S, SO2, and NO on the Li2MnO3 crystal surface by experimental and first-principles studies

Abstract

This study delves into the surface reactivity of Li₂MnO₃ towards H₂S, SO₂ and NO gases at room temperature, employing both experimental and theoretical calculations. Li₂MnO₃ was synthesized using a conventional solid-state method. Then, Li₂MnO₃ was exposed to 100 ppm concentrations of the aforementioned gases, with subsequent spectroscopic and X-ray diffraction analyses, revealing gas-surface interactions within a few atomic layers. X-Ray diffraction demonstrated minimal structural changes post-gas exposure, indicative of surface-level reactions. X-Ray photoelectron spectroscopy and theoretical calculations unveiled the dissociative adsorption of H₂S, resulting in various oxidized sulphur species. H₂S reactivity was most pronounced at Mn sites, where H₂S donated electrons during the process. SO₂ adsorption yielded sulphate species, facilitated by electron transfer to Mn-sites. Conversely, NO adsorption identified distinctive Li and Mn sites on the oxide surface. By combining experimental and theoretical insights, it has been confirmed that the chemisorption of these toxic gases over the Li₂MnO₃ surface is pertinent to their effective removal across temperature ranges. This work advances the utility of Li₂MnO₃ in diverse gas treatment applications.