Effect of β-zeolite nanoclusters on the acidity and hydrodesulfurization activity of an unsupported Ni Mo catalyst

Acid Modification of the Unsupported NiMo Catalysts by Y-Zeolite Nanoclusters

“…Pore Diameter(nm) The SEM diagrams of the unsupported NiMo catalyst before and after modification were shown in Figure 4. The octahedral structures can be found in catalyst NiMo-1.5, which can be attributed to ammonium nickel molybdate crystal phase [18,41,42]. After modification, the octahedral ammonium nickel molybdate crystal phases disappear, the whole structure is in an amorphous state, indicating that the crystallization of ammonium nickel molybdate can be restricted by the Y-zeolite nanoclusters, and the same results are shown by the XRD (Figure 5).…”

“…The unsupported NiMo catalysts were prepared according to the previously reported method [10,18,30]. The unsupported NiMo catalyst precursor was synthesized by preparing an aqueous solution of ammonium heptamolybdate, ammonia water, and nickel nitrate with a molar ratio of Ni and Mo (1.5:1).…”

“…At the same time, the hydrotreating activity was greatly improved. However, the higher hydrogenation activity of the unsupported catalysts can produce deep hydrogenation for the impurities in diesel, which increases the hydrogen consumption and the complexity of the reaction [18]. It is not conducive to efficient and low-cost industrial production.…”

“…Furthermore, unsupported catalysts have weak acidity due to the lack of the support [18]. Solid acids including Lewis and Brønsted acid sites are related to the isomerization and cracking activity of the catalyst [19][20][21], and play an important role in the catalytic reaction.…”

“…The suitable Lewis and Brønsted acid sites are beneficial to the improvement of the isomerization and cracking activity of the catalyst [22,23]. However, the unsupported catalysts have only the weak Lewis acid site [18], and it can only be used for hydrogenation but not for isomerization and cracking reactions, which leads to great limitations. To improve the acidity of the unsupported catalysts, the alumina was added to the unsupported catalysts, but the acidity of the unsupported catalysts was not significantly improved due to the weak acidity of alumina.…”