Electronic properties of unsupported trimetallic catalysts

• Computational calculations were carried out on terms of extended Hückel method.
• The trimetallic unsupported M–Mo–W–S (M = Ni, Co, Fe or Cu) sulfide catalysts were studied.
• Configuration 2H-MoS2, Mo–W–S and Mo–W–M–S where M = Ni, Co, Fe or Cu.
• Electronic properties, such as band structure and the density of states, were identified.
• Availability of electrons over the Fermi level increased intensifying the metallic character.

It is well known that the catalytic activity that presents a particular sulfide depend upon the transition metal that it possesses and of its location in the periodic table. In order to gain insight into the origin of these trends in activity, on terms of extended Hückel method, were carried out calculations for trimetallic unsupported M–Mo–W–S (M = Ni, Co, Fe or Cu) sulfide catalysts. The results of these calculations were used to identify electronic properties, such as band structure, density of states and average net charge, which showed that exists a direct correlation with the catalytic activity of the transition metal sulfides. In addition, was observed that the promotion of (Mo–W)S2 precursors with M to form trimetallic M–Mo–W–S catalysts after sulfidation, increases the availability of electrons over the Fermi level, increasing the metallic character of the catalysts.

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