Effect of Metal Oxide–Support Interactions on Ethylene Oligomerization over Nickel Oxide/Silica–Alumina Catalysts

Abstract

We investigated the interactions between nickel oxide and silica–alumina supports, which were applied to the catalytic oligomerization of ethylene by powder X-ray diffraction, UV diffuse reflectance spectroscopy, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic activity was also correlated with the acidity of catalysts determined by NH3 temperature-programmed desorption and pyridine FT-IR spectroscopy. Although all the catalysts had similar Ni contents, their catalytic performances were strongly influenced by the strength of the metal oxide–support interaction. Strong interaction promoted the formation of nickel aluminate on the catalyst surface, and resulted in low catalytic activity due to reducing the amount of nickel oxide active sites. However, weak interaction favored the aggregation of nickel oxide species into larger particles, and thus resulted in low ethylene conversion and selectivity to oligomers. Eventually, the optimal activity was realized at the medium interaction strength, preserving a high amount of both active nickel oxides and acid sites.

Simple Synthesis and Characterization of Shell-Thickness-Controlled Ni/Ni3C Core-Shell Nanoparticles

“…Since nickel naturally oxidizes, such oxidation-related peaks appear for Ni Nps. The results of previous studies support the assignment of BEs of 852.6, 855-856, and 857-858 eV in the Ni 2P 3/2 XPS spectra for Ni0, Ni 2+ , and Ni 3+ in oxidized Ni, oxides, and hydroxides and oxyhydroxides, respectively[27][28][29]. The BE of 860.2 eV is characteristic of related satellite peaks.…”

Tuning the Ni site location of bifunctional Ni-based catalysts for improving the performance in ethylene oligomerization

“…However, reflections at 37.2°, 43.3°, and 62.9° corresponding to the (111), (200), and (220) planes of the NiO phase (JCPDS 04-0835) are perceived only in the PM-2.5% (2.5 wt% Ni) catalysts. 10,22,30 This result indicates that the Ni in IWI-2.5% (2.5 wt% Ni) and IE-2.5% (2.5 wt% Ni) samples shows good dispersibility in the carrier. Meanwhile, the uniform distribution of Ni can effectively avoid the deactivation of the catalyst due to the sintering effect, 31 thereby promoting the stability and reaction activity of the catalyst.…”

“…However, the effects of Ni site distributions for ethylene oligomerization have rarely been studied. [21][22][23] How to control and describe the Ni site distribution? Some reference studies reported methods for controlling the location of metals (Pt, Pd, etc.)…”

Synthesis and Application of Zeolite Catalysts

“…MgO impregnated Al 2 O 3 was investigated in the catalytic decomposition of hydrofluorocarbon, which confirmed that the weak Lewis acid site of Al 2 O 3 and basic sites of Mg were advantageous for the high activity and catalyst lifetime [22]. NiO was also supported on SiO 2 -Al 2 O 3 support via metal oxide-support interaction, in which the medium interaction strength preserving the active nickel oxides and acid sites was important for achieving optimal catalytic activity in ethylene oligomerization [23]. Pt metal nanoparticle embedded Co-based metal organic framework was pyrolyzed to porous carbon Pt@Co/C composite, which could be used as the Fischer-Tropsch catalyst achieving 35% CO conversion with various hydrocarbons at low pressure [24].…”