Physical and chemical properties of WS2 catalysts

Abstract

1. An x-ray structural investigation was made of WS2 catalysts with different W: S ratios and different catalytic activities. 2. Regardless of the W: S ratio (within the limits of WS2.30- WS1.862), the WS2 catalysts consisted of only one crystalline phase, WS2, with identical lattice parameters. 3. WS2 catalysts with excess sulfur above the stoichiometric amount for the formula WS2, did not contain the sulfide of hexavalent tungsten WS2. 4. The excess sulfur above the stoichiometric amount was not incorporated into the crystal structure of WS2 as a result of the deficit of tungsten atoms in it. 5. The crystal structure of the WS2 phase was disordered; it consisted of small, fine blocks of WS2 layers, randomly displaced relative to each other. When WS2 catalysts were briefly heated, appreciable ordering of the crystal structure only occurred above 700°.