Hydrodeoxygenation of lignin-derived diphenyl ether on in situ prepared NiMoS catalyst: The effect of sulfur addition on catalyst formation

Abstract

The catalytic activity of unsupported NiMoS catalysts prepared in situ by thermal decomposition of the [(CH3)3S]2Ni(MoS4)2 precursor was studied in the course of diphenyl ether hydrodeoxygenation. The resulting catalysts were characterized using the transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was demonstrated that the diphenyl ether conversion naturally decreases with a decrease in the precursor loading. The effect of changes in the amount of the added sulfiding agent on the morphological and structural features of the formed catalysts was studied. It was found that reducing the amount of elemental sulfur from 2.5 to 0.5 wt% results in a more active sulfide NiMo catalyst, which is explained by an increase in the dispersion of the active phase particles from 0.24 to 0.34. A route of diphenyl ether hydrodeoxygenation on unsupported NiMoS catalysts was studied and suggested by varying the reaction time and hydrogen pressure in the system.