Hydrogen intercalates of low-dimensional dichalcogenides of transition metals

Temperature dependences of electrical conductivity and magnetic susceptibility of intercalates HxNbSe2 (0 ⩽ x ⩽ 5.2) and DxNbSe2 (0 ⩽ x ⩽ 0.53) have been studied. A change of the metallic type of conductivity for the semiconducting one for HxNbSe2 (x > 1) is related to the structural transition of the 2HTaS2 → 2HMoS2 type. DxNbSe2 (with the exception of x = 0.41) has a metallic type of conductivity. HxNbSe2, DxNbSe2 are paramagnets. Their magnetic susceptibility at small contents of hydrogen (deuterium) depends weakly on the temperature. At x > 1 the magnetic susceptibility of intercalates changes according to the Curie-Weiss law. The 2HNbSe2 treatment with the hydrogen plasma leads to the formation of the HxNbSe2 intercalates with the 2HTaS2 and 2HMoS2 structural type. The temperature rise results in the formation of only 2HTaS2 structural type. Hydrogen intercalates in considerable quantities in 2HWSe2 and 2HMoSe2 (HxWSe2:0 < x < 3.9; HxMoSe2:0 < x < 2.08) with the dominating intercalation of hydrogen on cooling. 2H-WSe2 possesses improved sorption properties as compared to 2HMoSe2. Hydrogen intercalates of layered dichalcogenides of d-transition metals are promising as new hydrogen-containing materials applied for different purposes.