Preparation of Unsupported NiMoP Catalysts for 4,6-Dimethyldibenzothiophene Hydrodesulfurization.

The preparation of unsupported NiMoP catalysts in the presence of citric acid (CA) is reported. Phase pure NiMoP with a surface area ~60 m/g was synthesized in the presence of CA at low reduction temperature (550 °C), with a Ni/Mo/P molar ratio of 1/1/1 and a 1.5 CA/Me ratio (Me = Ni + Mo). Depending on the synthesis conditions, small amounts of MoP and NiMoP were also present in the catalysts. The catalyst precursors appeared similar to those identified for MoP and NiP catalysts, also synthesized in the presence of CA. For the phase pure NiMoP catalysts, the TOFs for the HDS of 4,6-dimethyldibenzothiophene were almost identical, despite large differences in NiMoP surface area and crystallite size. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]