XAFS studies on highly dispersed Ni2P/SiO2 catalysts for hydrodesulfurization of 4,6-dimethyldibenzothiophene

The Ni2P catalysts were prepared by a new synthetic method with the use of less oxidic phosphorus precursor in order to achieve high dispersion on silica support, and their structural properties and catalytic activity in HDS of 4,6-DMDBT were studied. Comparison was made with a conventionally prepared sample which was obtained by temperature programmed reduction method. Various characterizations were conducted by BET, CO uptake, TPR, XRD and X-ray absorption spectroscopy. The amounts of CO chemisorption uptake were 64 and 20 μmol g−1 for Ni2P/SiO2-LT and Ni2P/SiO2-HT, respectively, indicating that the low temperature reduction technique led to better dispersion of Ni2P particles on SiO2 support. The catalytic activity in the HDS of 4,6-DMDBT followed the order, Ni2P/SiO2-HT(54%)<Ni2P/SiO2-LT(67%). The order correlated well with the amount of CO uptake. These results thus suggest that the HDS activity of the Ni2P catalysts highly depend on the dispersion of the Ni2P phase.