Hydrogen activation on alumina supported MoS2 based catalysts: Role of thepromoter

The properties of alumina-supported Mo and NiMo sulfides toward a hydrogen atmosphere were investigated in order to elucidate if the synergy observed in hydrotreating reactions might be related to the activation of hydrogen. The determination of the amount of adsorbed hydrogen and of the H-2-D-2 exc hange rate for various reduced states has evidenced that Ni does not promot e the reducibility and the amount of adsorbed hydrogen of the MoS2 phase wh ile the exchange rate is increased only by factor of 2-3. It is concluded t hat the synergy observed in hydrotreating reactions does not come from hydr ogen activation limitation. (C) 1999 Academic Press.