Effect of EDTA at pH = 7 on oxidized NiMo/Zr-SBA-15 catalysts oriented to hydrodesulfurization processes

Abstract This study reports the beneficial effect of EDTA insertion at neutral pH on oxidized NiMo catalysts supported on Zr-SBA-15 with a theoretical molar ratio of Zr/Si = 0.07, synthesized by the sol–gel method. The support was impregnated with the precursor solutions of nickel nitrate and ammonium molybdate in order to obtain NiMo bimetallic catalysts with a theoretical molar ratio of Ni/(Ni + Mo) = 0.3. In addition, EDTA was incorporated as a chelating agent during the impregnation step with a theoretical molar ratio of Ni: EDTA = 1:1 adjusting the pH to neutral. The bimetallic catalysts were characterized at each step of the preparation (drying and calcination). XRD, N 2 physisorption, and TEM analyses demonstrated that the incorporation of metals did not considerably affect the mesoporous morphology, as evidenced by the persistence of the support’s characteristic reflections. Both synthesized catalysts demonstrate adsorption–desorption isotherms type IV and H1-type hysteresis characteristic of mesoporous materials with uniform morphology. Likewise, EDTA at neutral pH increased the NiMoE/ZS07 catalyst’s specific surface area near 615 m 2 /g, 73% more than that of the catalyst without a chelating agent. FTIR analysis suggests the adsorption of nickel nitrate and ammonium molybdate salts and the thermal decomposition of EDTA. UV–Vis DRS and Raman spectroscopy analyses described that the addition of EDTA at neutral pH together with the calcination conditions significantly reduced the support-deposited species interaction and increased the interaction between metals. The use of the material as a hydrodesulfurization catalyst was enhanced by the modification of the oxidation state of the deposited oxidic molybdenum, as reported by XPS spectra analysis. Graphical Abstract Schematic representation of the effect of EDTA at pH = 7 that promotes a significant contribution to the dispersion of Mo species in the oxide phase on the ZS07 support