NI AND W EXAFS OF NI-WS2 C HYDROTREATING CATALYSTS/

W L(III) EXAFS of WS2/C and Ni-WS2/C catalysts showed that the WS2/C c atalyst contains small WS2 particles of about 7 W atoms, while the Ni- WS2/C catalyst contains larger particles. Ni K EXAFS demonstrated that the Ni atoms were present at the edges of the WS2 particles in a Ni-W -S like structure, like the Ni-Mo-S structure in Ni-MoS2/C catalysts. In the Ni-WS2/C catalysts Ni is, however, coordinated by six sulphur a toms, four at 2.22 angstrom and two at 2.35 angstrom from the Ni atom.