Intercalation of ammonia into tantalum disulfide

Abstract

Publication costs assisted by Exxon Research and Engineering CompanyIn an effort directed toward a more thorough comprehension of the process of intercalation of Lewis-base guests into the layered transition metal dichalcogenides, we studied the gas-solid reaction of ammonia and tantalum disulfide. The uptake and desorption were followed gravimetrically. Isotherms for (NH3)xTaS2 between 308 and 353°K and 0.65 < x < 0.85 did not show hysteresis. In this concentration range, the variation of composition with temperature at constant NH3 pressure (1 atm) shows the presence of a simple homogeneous phase. This is confirmed by X-ray diffraction. Deintercalation below x ~0.65 leads to the formation of a second-stage compound. In the single phase region, the isosteric enthalpy of intercalation increases with increasing ammonia content. This suggests strong interaction between intercalated molecules and a structure having the C3 axis of the guest parallel to the layer planes.

Intercalation and Deintercalation Processes for Ammoniated 1T-TaS2

“…Complete intercalation was not observed, even for samples that were reacted with NH for several months. This behavior is in contrast to the essentially complete ammonia intercalation of 2H-TaS 2 in several hours (33). Sonication and repetitive intercalation/deintercalation of NH increased the amount of NH intercalated, but still did not lead to substantial intercalation.…”

“…The ammonia and ammonium deintercalation enthalpies for ammoniated 1T-TaS 2 are consistent with those obtained for ammoniated TiS (34), NbS (17), and 2H-TaS 2 (33). The deintercalation enthalpies for these four ammoniated hosts are summarized in Table 2.…”

Hole Reactions from d‐Energy Bands of Layer Type Group VI Transition Metal Dichalcogenides: New Perspectives for Electrochemical Solar Energy Conversion

“…Electron transfer from Oil-is thus suppressed while transfer from I-is still possible and the generation of photocurrent is considerably facili- These arguments provided for a complex formation between reducing agents and vacant d-states in transition metal-dichalcogenide layer crystals receive substantial support from the remarkable crystal-chemical property of these compounds. ~hey belong to a class of lamellar hosts capable of intercalating organic compounds between the composite sheets of their chalco.-genide-transition metal-chalcogenide sandwiches (15,(28)(29)(30)(31)(32)(33)(34). A most interesting detail is that the guest molecules have to be Lewis bases (e.g., ammonia, pyridine) or electron donating species (such as alkali metals) and another one that the intercalate formation with organic molecules works well with layer crystals belonging to Group V transition metals (TaS2, NbS2), in which the low energy d-bands are only half filled, giving them metallic character, but not with those belonging to Group VI transition metals (MoS2, WS2) which are semiconductors with full d-bands (29).…”

Solvated Intercalation Compounds of Layered Chalcogenide and Oxide Bronzes

“…The initial rate of the gas-solid reaction is dominated by a nucleation period with the occurrence of higher-stage phases (53,54). The initial rate of the gas-solid reaction is dominated by a nucleation period with the occurrence of higher-stage phases (53,54).…”