Surface characterization of bulk Fe–Mo mixed sulphide catalysts

Difference of work function potential measurements and X-ray photoelectron spectroscopy (XPS) were used to characterize bulk Fe–Mo mixed sulphides. Thiophene hydrodesulphurization (HDS) and toluene hydrogenation (HYD), at high pressure, were used as catalytic tests. A clear synergetic effect is observed for both reactions. According to difference of work function potential values, mixed sulphides are not a mixture of Mo and Fe sulphides but rather Fe–Mo bimetallic sulphides. They also suggest electron enrichment around the Fe atom for mixed sulphides.