Characterization of Fe and Ni-promoted unsupported MoS2 catalysts and their precursors via thermal effects in temperature-programmed reactions

Abstract

Precursors of unsupported NiMo and FeMo sulfide hydrodesulfurization catalysts with concentration ratiosr=Ni(Fe)/(Ni(Fe) + Mo) ranging from 0.1 to 0.3 were prepared by three methods: homogeneous sulfide precipitation (HSP), inverse HSP and coprecipitation. Differential thermal analysis was used to study the decomposition under argon, and the reduction/sulfidation under 15% H2S—H2 of the precursors and the subsequent oxidation under air of the samples obtained after these reactions. The reactivity of the solids varies as a function of the preparation method, the nature of the promoter and the concentration ratio. The degree of sulfidation of the precursor and the presence of either NH4NO3 or NH2Cl formed from group VIII metal salts and (NH4)2S may affect the thermal behaviour of samples during DTA.