Carbon nanofibres coated with Ni decorated MoS2 nanosheets as catalyst for vacuum residue hydroprocessing

9 págs.,7 figures, 3 tablesCatalysts based on functionalised carbon nanofibers (FCNF) coated with Ni-decorated MoS2 nanosheets were obtained by direct decomposition of ammonium thiomolybdate and nickel nitrate impregnated on the FCNF under controlled temperature conditions in inert atmosphere. The catalysts were characterised by X-ray diffraction (XRD), N2 adsorption, Raman spectroscopy, temperature programmed reduction of sulfur species (TPR-S), NH3 temperature programmed desorption (NH3-TPD) and transmission electron microscopy (TEM). Decomposition temperature was found to have a paramount importance in the formation of uniform MoS2 slabs, as revealed by the TEM study: at 600°C, non-uniform covering of the carbon nanofiber (CNF) was observed together with the presence of small round-shaped metal particles (ca. 20nm). On the other hand, at 450°C CNF appeared homogeneously covered by amorphous MoS2 slabs decorated with Ni, resulting in higher amount of coordinated unsaturated sites (CUS), as determined by TPR-S. Catalysts were tested in the hydroprocessing of a vacuum residue and the results were compared against a benchmark alumina-supported NiMo catalyst. Higher asphaltene conversions were obtained for the CNF-supported catalysts prepared at 450°C, which overperformed the Al2O3-supported benchmark catalyst. However, the catalytic performance in hydrodesulfurisation and hydrodemetallisation of the CNF-based catalysts was slightly lower than that of the benchmark catalyst.J.L.P. thanks the Spanish MEC for a personal grant (Spanish Scientists Mobility Program, ref. EX2009-0822). H.P., D.T and S.d.LL. thank CSIC for the funding of the short stays at ICB-CSIC or Imperial College (project I-LINK ref.0439). H.P. and S.d.LL. thank the support of CONACYT Mexico and DGA (Spain), respectively, for the award of their PhD grant. DT thanks the support of FEDER and Spanish Ministery of Economy and Competitiveness for the award of his PhD grant under the frame of the research project ENE2011-28318-C03-01.Peer Reviewe