Activity in hydrotreatment processes of Ni-Mo loaded zirconium phosphate Zr-3(PO4)(4)

Amorphous zirconium phosphate Zr-3(PO4)(4) (referred to as ZrP) with a spec ific surface area of 114 m(2) g(-1) was prepared by a sol-gel method. Its a cid properties were studied by: 1. butan-2-ol conversion 2. LR spectroscopy of adsorbed pyridine and 3. microcalorimetric measurements of heat of ammo nia adsorption, It was found that the sample exhibits two kinds of acidic B ronsted sites and also Lewis acidity. The strongest acid sites retained pyr idine until 623 K. True Lewis acidity was associated with zirconium atoms e merging on the surface of the sample. Sulfided samples of Mo/ZrP and NiMo/Z rP were tested in biphenyl hydrogenation, thiophene hydrodesulfurization an d pyridine hydrodenitrogenation. Their intrinsic activities were significan tly higher than an industrial NiMo/Al2O3 catalyst. Catalyst characterization by conventional spectroscopic techniques did not show any crucial difference between NiMo/ Al2O3 and NiMo/ZrP, However, on t he sulfided samples, electron microscopy observations revealed that the MoS 2 crystallites are very well dispersed on the support and smaller on ZrP th an on alumina. In addition, the stacking of MoS2 layers was found to be equ al to 1.6 when using ZrP instead of 2 on Al2O3 All these features were corr elated to the catalytic performances of the samples and to ZrP surface prop erties that are believed to contribute to the stabilization of highly dispe rsed MoS2 species. (C) 1999 Elsevier Science B.V. All rights reserved.