Influence of the Iron Proportion on the Efficiency of an Oil-soluble Ni-Fe Catalyst Applied in the Co-liquefaction of Lignite and Heavy Residue

Developing a fundamental insight into the active phase and the component–activity relationships of catalysts is critical to the successful design of highly efficient catalysts. The influence of the iron proportion on the performance of synthesized Ni–Fe catalysts was investigated to modulate the intrinsic catalytic activity. Furthermore, characterization features of sulfided catalysts and density functional theory methodology were combined for a comprehensive interpretation. The highest hydrogenation efficiency occurred with nickel and iron in an equimolar ratio. A significant increase in the degree of nickel sulfidation was found to coincide with an increase in the proportion of iron, which is ascribed to a lowered thermal decomposition temperature and the promotion of sulfur adsorption. In addition, benefiting from the considerably stronger H adsorption to facilitate H2 dissociation, the (Fe,Ni)9S8 phases, which exist in all sulfided catalysts, should to be the key component responsible for the observed...