Preparation of highly dispersed W/ZrO2–Al2O3 hydrodesulfurization catalysts at high WO3 loading via a microwave hydrothermal method

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

“…As mentioned earlier, the research directed to modulate the metal-support interaction can be envisaged from many viewpoints, such as the use of crystallographic phases different from the typical gamma alumina [38] or supporting the active phases over unconventional single metal (Ms) oxides such as those based on Ti [26,[39][40][41][42][43][44][45], Zr [26,[41][42][43][44]46,47], Si [23,26,[48][49][50] or Ga [51]. Nevertheless, more recently to gain advantage from the individual single metal oxide properties and to overcome their intrinsic limitations, several binary mixed oxide materials such as Al2O3-Ga2O3 [50], Al2O3-TiO2 [4,52-57], ZrO2-TiO2 [35,58,59], Al2O3-ZrO2 [60][61][62], MgO-TiO2 [63], Al2O3-MgO [56,64], Mn-Al2O3 [65][66][67], and Al2O3-zeolite [68] have been studied, among several others that have been tested to prepare HDS catalysts. As expected, in several cases higher activities of catalysts prepared over those mixed oxides were reported compared with those supported on alumina.…”

Nb2O5-γ-Al2O3 nanofibers as heterogeneous catalysts for efficient conversion of glucose to 5-hydroxymethylfurfural

“…At low Nb 2 O 5 loading, the niobia species dispersed on the γ-Al 2 O 3 nanofiber support through Nb–O–Al bridge bonds. γ-Al 2 O 3 has Lewis acid sites with different acid strengths and weak Brønsted acid sites, and the reaction between Nb 2 O 5 precursor and hydroxyl groups on the surface of γ-Al 2 O 3 nanofiber results in strong metal-support interaction, generating Nb 2 O 5 -γ-Al 2 O 3 nanofiber with both strong Lewis acid sites and relatively intensive Brønsted acid sites14. With the increase of Nb 2 O 5 loading, the interaction between the isolated niobia species and their nearest neighbors (either isolated or polymerized species) resulted in the formation of Nb–O–Nb bridge bonds.…”

“…Herein, Nb 2 O 5 loading increase could lead to the formation of two-dimensional polymerized niobia species, three-dimensional polymerized niobia species and crystallization, which influenced the distribution and quantity of the Lewis acid sites and Brønsted acid sites. On one hand, the Lewis acid site Nb δ+ play a key role on the isomerization of glucose to fructose, and Brønsted acid sites are more active in the dehydration of generated fructose to 5-HMF1432. The heterogeneous catalyst with the suitable ratio of Lewis acid sites to Brønsted sites should display an more excellent catalytic performance in the conversion of glucose to 5-HMF in organic solvents33.…”

“…As for the heterogeneous catalysts, besides the main catalytic active sites like metal oxides such as WO 3 , TiO 2 , and ZrO 2 , the supports also play a very important role on catalytic process1415. Generally, the conventional porous materials were used as supports because of their large surface areas.…”

The Influence of Pore Structure and Acidity on the Hydrodesulfurization of Dibenzothiophene over NiMo-Supported Catalysts

“…Nowadays, γ-Al 2 O 3 as a traditional support has been widely applied in industrial processes owing to its characteristic advantages − including (1) low cost, (2) good stability, (3) high tolerance for longevity, and (4) good regeneration capacity. On the contrary, it also has the following drawbacks, − i.e., undesirable surface area and pore diameters as well as unconcentrated pore diameter distributions, which restrict the complete removal of macromolecular sulfides like benzothiophene, dibenzothiophene, and derivatives. Zeolites, − such as beta, ZSM-5, and Y, are excellent candidates for catalyst carriers since their regular configurations, shapes, pore sizes, and excellent connectivity of channels could provide huge potential for high activities.…”