Research NoteXPS study of a bulk WP hydrodesulfurization catalyst

•The actual active surface of the bulk WP catalyst is a sulfur-containing phase.•The formation of the tungsten phosphosulfide phase is fast.•The presence of sulfur decreases the electron densities of the surface WP species.•Strong adsorption of NH3 (formed by the hydrodenitrogenation of piperidine) on WP.•NH3 is a strong poison for the metal phosphide hydrodesulfurization catalysts.

The X-ray photoelectron spectroscopy characterization of a bulk WP hydrodesulfurization (HDS) catalyst demonstrated that the actual active surface phase of WP in the HDS of dibenzothiophene (DBT) is a sulfur-containing phase. This tungsten phosphosulfide phase formed faster than the molybdenum phosphosulfide phase, but possessed a lower sulfur content than the corresponding Ni2P and MoP phases. NH3 was the dominant nitrogen-containing species detected in the WP catalyst after simultaneous HDS and hydrodenitrogenation reactions. NH3 decreased the DBT conversion strongly but less than piperidine, indicating that not only N-containing compounds but also NH3 inhibits the HDS activity of WP.

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