Catalytic Performance of NiMoS Supported on (Zr)SBA-15 for Hydrodesulfurization of Diesel: Insight into a One-Step Calcination and Reduction Strategy during Sulfidation

Abstract

We report, herein, the catalytic efficiency and activity of a facilely synthesized sulfided NiMo hydrodesulfurization (HDS) catalyst supported on (Zr)-SBA-15 by one-step calcination and reduction heat treatment prior to sulfidation. Zr-SBA-15-Mo is prepared by a direct synthesis approach, followed by the confinement of Ni into the assynthesized Zr-SBA-15-Mo without calcination, to generate more dispersion and active sites of metal oxides for an efficient sulfidation process. The HDS performance of these catalysts was evaluated and compared to that of the catalysts prepared by the sequential calcination and reduction approach prior to sulfidation for HDS of dibenzothiophene (DBT) and dimethyldibenzothiophene (DMDBT) in commercial diesel at 350 °C in batch reactor mode. Structural and morphological properties related to catalytic activity have been obtained by means of spectroscopy (X-ray diffraction (XRD), Raman, pyridine-Fourier transform infrared (FTIR), temperature-programmed desorption (TPD), microscopy (scanning electron microscopy)), and N 2 physisorption. The characterization and investigations from XRD, Raman, pyridine-FTIR, and TPD revealed that avoiding multiple heat treatment in designing HDS catalysts provides more coordinative unsaturated active sites necessary for better catalyst performance and stability. In addition, the textural properties (specific surface area, pore size, and volume) that allow easy diffusion of reactant molecules are better preserved. The activity of the sulfided NiMo catalysts prepared by one-step heat treatment is 9−16% higher for DBT and 11−13% higher for DMDBT at 1 h reaction time compared to that of the catalysts prepared by sequential calcination and reduction before sulfidation. The catalysts prepared by this heat treatment approach have desulfurization efficiencies of 99 and 84% for DBT and DMDBT, respectively.

Hydrotreating of Methyl Esters to Produce Green Diesel over Co- and Ni-Containing Zr-SBA-15 Catalysts

“…Thus, Zr-containing SBA-15 has been employed as an effective support for Co to prepare Fisher-Tropsch catalysts [34,35]. In the same way, hydrodesulfurization catalysts, showing enhanced activity, have been prepared by supporting Mo, CoMo and NiMo phases on Zr-SBA-15 [36][37][38]. According to these works, the presence of Zr on the SBA-15 material provides a tunable acidity and increases the dispersion and reduction degree of the metal phases, which in turn provokes an improvement of the catalytic properties.…”

Zirconia-Based Solid Acid Catalysts for Biomass Conversion

“…[105][106]108 Through onestep calcination and reduction heat treatment before sulfidation, Ganiyu and Alhooshani facilely synthesized an efficient NiMo/Zr-SBA-15 catalyst, which presents better catalytic performance and stability in hydrodesulfurization of dibenzothiophene and dimethyl dibenzothiophene than those of the catalysts prepared via sequential calcination and reduction prior to sulfidation. 38 At the same time, it was found that there is a synergistic effect of Zr and Ce in the catalysts of ZrO x -CeO x -NiMo-SBA-15 applied in hydrodesulfurization since the metal sites induce a strong hydrogen bond network that leads to a higher surface stability. 109 The overall applications of zirconia-based catalysts supported on SBA-15 are summarized in Table 2 (entries 35−43).…”

“…To date, zirconia-based catalysts have been involved in a variety of catalytic reactions. For instance, zirconia-based materials are regarded as one of the most promising catalysts in the industrial biodiesel production from vegetable and nonedible oils, which is a hot area for the blue print of long-lasting development of energy. − The modification of zirconia can improve the acidity and accessibility of active sites on surface, enhancing the activity of zirconia-based catalysts in biofuels production. − Meanwhile, the applications of zirconia-based catalysts are spread over the area of syngas production. − Biomass refining reactions including dehydration, isomerization, transferhydrogenation, hydrodesulfurization, alcoholysis, hydrolysis, esterification, and etherfication are also comprehensively studied. − …”

Experimental and Theoretical Investigation of the Synergy Effect of Zr and Ce on the Catalytic Efficiency of NiMoS Grafted on SBA-15 for Oil Hydrodesulfurization

“…Different modification strategies such as addition of heteroatoms, additives, and choice of solvent have been reported . Heteroatoms that are Lewis acids such as zirconia, titania, and alumina increase the metal–support interaction from weak (which is known for silica) to moderate by increasing the acidity of SBA-15. , Different synthesis approaches have been explored to incorporate heteroatoms to SBA-15 and their effect on the catalyst HDS performance has been reported. − Chelating agents such as ethylenediaminetetraacetic acid (EDTA) and citric acid have great impact on the HDS performance of the catalysts . Badoga et al studied the combined effect of EDTA and heteroatoms (Ti, Al, and Zr) on the catalytic performance of an SBA-15-supported NiMo catalyst for hydrotreating applications .…”