Effect of Gallium as an Additive Over Corresponding Ni–Mo/γ-Al2O3 Catalysts on the Hydrodesulfurization Performance of 4,6-DMDBT

Abstract

Experiments were carried out to research the different contents of Ga2O3 modification effects on the hydrodesulfurization (HDS) performance of 4,6-dimethyldibenzothiophene (4,6-DMDBT) catalyzed by the stepwise impregnation method. Characterization techniques such as XRD, BET, HRTEM, NH3-TPD, and Py-FTIR were performed to determine the effects of each modification of the catalyst by Ga on the properties of the prepared supports and catalysts. The catalytic effect of gallium is reflected in the fact that the empty d-orbitals of Ga elements participate in the formation of molecular orbitals in the active center and change their orbital properties, thus generating a direct desulfurization active phase suitable for complex sulfides for endpoint adsorption. The characterization results indicated that the introduction of Ga2O3 with appropriate content (2 wt.%) promoted Ni and Mo species to disperse uniformly and doping of more Ni atoms into the MoS2 crystals, which also increased the average stacking number and the length of MoS2. As a result, more NiMoS active phases were favored to form in the system. The specific surface area and the amounts of acid sites were increased, facilitating the adsorption of reactant molecules and the HDS reactions. The HDS results also suggested the effects of Ga modification play a very important role in the catalytic performance of the corresponding catalysts. The catalyst Ga–Ni–Mo/Al2O3 exhibited the highest conversion rate towards 4,6-DMDBT HDS when the amount of Ga2O3 loading was 2 wt.% with an LHSV of 2.5 h−1 at 290°C and Ga modification also can effectively improve the direct desulfurization (DDS) route selectivity in varying degrees.

Catalytic conversion of sucrose to 1,2-propanediol over alumina-supported Ni–Mo bimetallic catalysts

“…The bands at 1445 cm À1 , 1575 cm À1 , and 1604 cm À1 correspond to the Lewis acid sites. According to the literature, [40][41][42][43] the sharp bands at 1445 cm À1 and 1604 cm À1 are attributed to the strong interaction of pyridine with the Lewis acid sites, while the weak band at 1575 cm À1 indicates weak Lewis-bound pyridine. Furthermore, the peak at 1489 cm À1 corresponds to the combination of Lewis and Brønsted acid sides.…”

Systematic analysis of the gallium ions and structure-directing agents in the preparation of NiW HDS catalysts over mixed oxides of Al2O3-TiO2

“…On the other hand, metal-support interaction is essential for electron transfer in catalysts prepared using multiple metals. Recently, there has been a rising concern about the use of additives such as Ga [26][27][28], P [29][30][31], Ti [32], Mg [33,34], and Ce [35,36] in the synthesis of desulfurization catalysts. These additives have been found to enhance the catalytic properties of the materials in which they were included [26,37].…”

“…Recently, there has been a rising concern about the use of additives such as Ga [26][27][28], P [29][30][31], Ti [32], Mg [33,34], and Ce [35,36] in the synthesis of desulfurization catalysts. These additives have been found to enhance the catalytic properties of the materials in which they were included [26,37]. Previous literature has shown that the addition of gallium to the surface alters the morphology of promoted MoS 2 slabs, enhances the activity of NiMo catalysts, and directly affects the conversion rate and selectivity of DDS and HYD routes to some degrees [38][39][40].…”

“…Moreover, Huang M et al (2022) observed that adding Ga as an additive promoted the dispersion of active species, allowing Ni atoms to decorate the MoS 2 crystals and increase the average stacking and slab length of MoS 2 . Finally, modifying NiMo/Al 2 O 3 catalysts with Ga can efficiently improve the selectivity towards the hydrogenolysis route [26,44].…”