Interplay Between Ni and Brønsted and Lewis Acid Sites in the Hydrodesulfurization of Dibenzothiophene

Ni-MoS2/γ-Al2O3 catalysts are commonly used in hydrotreating to enhance fossil fuel quality. The extensive research on these catalysts reveals a gap in understanding the role of Ni, often underestimated as an inactive sulfide phase or just a MoS2 promoter. In this work, we focused on analyzing whether well-dispersed supported nickel nanoparticles can be active in the hydrodesulfurization of dibenzothiophene. We dispersed Ni by Strong Electrostatic Adsorption (SEA) method across four supports with different types of acidity: silica (~ neutral acidity), γ-Al2O3 (Lewis acidity), H+-Y zeolite, and microporous-mesoporous H+-Y zeolite (both with Brønsted-Lewis acidity). Our findings reveal that Ni is indeed active in dibenzothiophene hydrodesulfurization, even with alumina and silica as supports, although their catalytic activity declines abruptly in the first hours. Contrastingly, the acid nature of zeolites imparts sustained stability and performance, attributed to robust metal-support interactions. The efficacy of the SEA method and the added mesoporosity in zeolites further amplify catalytic efficiency. Overall, we demonstrate that Ni nanoparticles may perform as a hydrogenating metal in the same manner as noble metals such as Pt and Pd perform in hydrodesulfurization. We discuss some of the probable reasons for such performance and remark on the role of Ni in hydrotreatment.

Pd4S/SiO2: A Sulfur-Tolerant Palladium Catalyst for Catalytic Complete Oxidation of Methane

Sulfur species (e.g. H2S or SO2) are the natural enemies of most metal catalysts, especiallypalladium catalysts. The previously reported methods of improving sulfur-tolerance were toeffectively defer the deactivation of palladium catalysts, but could not prevent PdO and carrierinteraction between sulfur species. In this report, novel sulfur-tolerant SiO2 supported Pd4Scatalysts (5 wt. % Pd loading) were prepared by H2S–H2 aqueous bubble method and applied tocatalytic complete oxidation of methane. The catalysts were characterization by X-ray diffraction,Transmission electron microscopy, X-ray photoelectron Spectroscopy, temperature-programmedoxidation, and temperature-programmed desorption techniques under identical conditions. Thestructural characterization revealed that Pd4S and metallic Pd0 were found on the surface of freshlyprepared catalysts. However, Pd4S remained stable while most of metallic Pd0 was converted toPdO during the oxidation reaction. When coexisting with PdO, Pd4S not only protected PdO fromsulfur poisoning, but also determined the catalytic activity. Moreover, the content of Pd4S could beadjusted by changing H2S concentration of H2S–H2 mixture. When H2S concentration was 7 %, thePd4S/SiO2 catalyst was effective in converting 96% of methane at the 400 °C and also exhibitedlong-term stability in the presence of 200 ppm H2S. A Pd4S/SiO2 catalyst that possesses excellentsulfur-tolerance, oxidation stability, and catalytic activity has been developed for catalyticcomplete oxidation of methane.

Highly efficient Fischer–Tropsch synthesis over an alumina-supported ruthenium catalyst

A highly active catalyst for Fischer–Tropsch synthesis at 423 K was prepared, on which the adsorbed CO dissociated at 303 K.

Conversion of bis(2-hydroxyethylene terephthalate) into 1,4-cyclohexanedimethanol by selective hydrogenation using RuPtSn/Al2O3

One-pot conversion of bis(2-hydroxyethylene terephthalate) derived from waste PET into 1,4-cyclohexanedimethano with high yield was achieved by trimetallic RuPtSn/Al₂O₃.

Effect of the thermal treatment temperature of RuNi bimetallic nanocatalysts on their catalytic performance for benzene hydrogenation

The thermal treatment temperature of bimetallic nanocatalysts plays an important role in determining their catalytic performance.

Efficient hydrogenation of aromatic aldehydes to corresponding benzyl alcohols over Ni–B/MIL-101

Ni–B amorphous alloy particles incorporated onto MIL-101 were prepared by a simple reduction impregnation method, and exhibited excellent catalytic activities for liquid-phase chemoselective hydrogenation of aromatic aldehydes to corresponding benzyl alcohols.