Modifying the catalytic properties of hydrotreating NiMo–S phases by changing the electrodonor capacity of the support

The hydrogenation activity and physico-chemical characterization of a series of NiMo catalyst supported on materials with different acid-base properties (Al2O3, layered double hydroxides-derived MgAl oxides and MgO) have been investigated. The results show a clear correlation between the electrodonor capacity of the support, the negative charge density of the supported NiMo oxides and the intrinsic hydrogenation rate of the sulfided phase. Spectroscopic characterization ruled out any possible contribution derived from differences in the NiMoS2 stack or slab size distributions, as determined by high-resolution transmission electron microscopy. The experimental results obtained suggest the occurrence of an electron transfer phenomena from the support to the supported NiMoS2 slabs, being this effect stronger for supports with higher electrodonor capacity. This work presents a specific electronic support effect that goes beyond the classical dispersing and stabilizing role.