Triblock Copolymer Effect During the Synthesis of ZrO2-TiO2 Mixed Oxides Supports for NiW Hydrodesulfurization Catalysts

Surfactant addition during support synthesis resulted in materials with defined porosity, smaller particle size, and the absence of segregated ZrO2 and TiO2 crystalline phases at least to the XRD detection limit. The data obtained by N2 physisorption showed improved textural properties compared with the individual pure oxides. The Ultraviolet–visible (UV–Vis) diffuse spectroscopy revealed broadband assigned to the mixed-phase. Meanwhile, the micrographs obtained by transmission electron microscopy showed nanometric domains of crystallinity and a worm-like morphology in all the samples. Raman spectroscopy showed the possible formation of the TiZrO4 forming the mixed oxides support. The chemical analysis performed by ICP-OES corroborates the expected equimolar relation Zr/Ti and the atomic ratio Ni/(Ni + W) approximately equal to 0.31. The support properties intrinsically influenced the WS2 nano slabs, as observed by TEM micrographs for the NiW/ZT-x sulfided series. The XPS analysis revealed that sulfidation degree increases and the highest amount of NiWS phase among all the materials are observed when the NiW system is deposited on the mixed oxides prepared with pluronic. The latter was also related to the reaction rates, where the sulfided NiW/ZT-x catalysts presented higher values than the NiW/ZT reference material. NiW/ZT-P sulfided sample showed the maximum reaction rate among the series studied.