Monodispersed tantalum disulfide and adsorption complexes with cations

Abstract

Cathodic electrolysis of 2H⋅⋅⋅TaS₂ in a dilute sulfuric acid electrolyte results in intercalation of hydrogen and water. The water content increases as the ionic strength of the electrolyte is decreased. Addition of neutral surfactants (1%−10% Triton X−705 or glycerol) followed by high−speed stirring gave TaS₂ layers monodispersed in the aqueous surfactant. Electronic absorption spectra of the dispersions agree well with spectra of cleaved solids. Dyes were used to study adsorption on the layers. Only cationic dyes were adsorbed and the adsorption was determined to be due to an ion exchange reaction with protons. Solid adsorption complexes were prepared by ultracentrifugation of the dispersion or by adding dyes to undispersed, water swollen TaS₂. The solid adsorption complexes gave no x−ray powder patterns, and were deficient in sulfur. Ac susceptibility measurements did not indicate bulk superconductivity in any of the complexes. Electron transfer from the TaS₂ layers to reducible dyes was observed, the apparent reduction potential being 0.25 V vs NHE.