Metal and acid sites instantaneously prepared over Ni/SAPO-11 bifunctional catalyst

Abstract

The Ni/SAPO-11 bifunctional catalyst for hydroisomerization of n-hexane was prepared via a novel synthesis method. It involved grinding of nickel source with amorphous precursors used for SAPO-11 followed by crystallization at 473 K for 24 h, thus avoiding the use of extra solvents in the synthesis. The highly dispersed nickel species and acid sites in the Ni/SAPO-11 bifunctional catalyst were instantaneouslyformed. The Ni/SAPO-11 catalyst contains framework nickel, nickel monoxide (NiO) and nickel aluminate spinel. The nickel monoxide with a size of 2-4 nm provides (de)hydrogenation function after reduction, while the framework nickel supplies more acid sites leading to an enhancedisomerization activity.The Ni/SAPO-11 catalyst shows a great synergeticeffect between the metallic nickel and acid sites with a high metal-to-acid sites ratio (C Ni /C A ) and close proximity. A single metallic nickel site is able to balance ca. 5 acid sites (C Ni /C A ≈0.19) over the Ni/SAPO-11 catalyst in n-hexane hydroisomerization.The high dispersion of nickel over the catalyst provides relatively excessive metal sites (C Ni /C A >0.19), leaving the rate limiting reaction to occur on the acid sites. The Ni/SAPO-11 catalyst exhibits comparable n-hexane conversion (71.2%) and iso-hexane yield (66.7%) to the classical Pt/SAPO-11 catalyst.With enhancing acidity, the Ni/SAPO-11 catalyst exhibits one of the highest iso-hexane yields reported in the n-hexane hydroisomerization, which render the new material as a promising candidate for the hydroisomerization catalysts.

n-Nonane hydroisomerization over hierarchical SAPO-11-based catalysts with sodium dodecylbenzene sulfonate as a dispersant

“…The relative crystallinities of S-S x (x = 1, 2, 3, 4 and 5) and S-C are 98.4%, 97.6%, 97.1%, 32.5%, 0% and 100%, respectively (Table S1). S-S x (x = 1, 2, 3 and 4) and S-C present characteristic peaks assigned to SAPO-11 (Zhao et al 2014;Lyu et al 2019). S-S 4 shows characteristic peaks with a lower intensity than S-C and S-S x (x = 1, 2 and 3), indicating the lower crystallinity of S-S 4 (32.5%).…”

Production of hydro‐processed renewable jet fuel over SAPO ‐11‐based catalyst

“…Another sample was prepared using the optimized metal (based on the highest conversion in the reactivity test) and SAPO-11 plus CA (CA: metal = 5:1, mol/mol) as an additional auxiliary agent to promote metal dispersion. 24 This sample was prepared with similar method mentioned above, the required amount of metal precursors and citric acid were first dissolved in ethanol. Then, the next steps completely followed the steps mentioned above.…”

“…21 Therefore, transition metals such as nickel, cobalt, and molybdenum, which exhibited good hydrodeoxygenation activity, 12,22,23 were chosen. In addition, Lyu et al 24 and Yuan et al 25 have provided the novel direct synthesis method and instant exactness synthesis method, respectively, for the catalyst preparation. Compared to traditional hydrothermal method, higher metal dispersion, acid sites, and proper metal-acid balance have been developed.…”

Hydroisomerization of n-Hexadecane Over Nickel-Modified SAPO-11 Molecular Sieve-Supported NiWS Catalysts: Effects of Modification Methods

“…As a result, improving the isomerization performance of SAPO-11 requires a better understanding of enhancing the proportion of medium and strong B acid sites. Lyu et al (2019a) used in situ synthesis to introduce varying amounts of Ni into SAPO-11 to investigate the effects of metal-acid balance on n-hexane hydroisomerization and the acidity of SAPO-11. However, up to now, no one has studied the effects of modification methods in the process of Ni modification on the physicochemical properties (such as textural and acidity) of SAPO-11 molecular sieves.…”