Carbon-Supported and Alumina-Supported Niobium Sulfide Catalysts

Allali, N.; Marie, A. M.; Danot, M.; Geantet, C.; Breysse, M.

doi:10.1006/jcat.1995.1255

Cited by 28 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Niobium is another easily accessible and cheap metal that has demonstrated great potential for HDS application. − However, the formation of NbS 2 from the highly stable Nb oxide is rare and is clearly explained from the perspective of its thermodynamics parameters and the combination of the elemental components (Nb and sulfur) at very high temperature (700–800 °C) resulting in metal sintering. , Recent advancement in the sulfidation of niobium oxide through the promoter effect of copper (Cu/Nb = 0.3) has been reported by Mansouri and Semagina . The choice of Cu as promoter was purely based on thermodynamic calculations of the energy parameters of severally cheap and available metals when in combination with Nb metal (Figure ).…”

Section: Active Phasesmentioning

confidence: 99%

Advanced Hydrodesulfurization Catalysts: A Review of Design and Synthesis

2019

View full text Add to dashboard Cite

Proliferating energy consumption, particularly of fossil fuels, has led to an increasing generation of pollutants; many of these harmful products have been of serious environmental concern. While energy demand will continue to grow due to massive urbanization and industrialization, the ability to remove such pollutants has not yet been achieved. Therefore, policies are always being reviewed to accommodate the existing reality of minimizing the amount of pollutants released to the environment on a daily basis. Sulfur dioxide, a major environmental pollutant, gets to the environment through the combustion of sulfur-containing fuel in the engine of automobiles. Over the years, regulatory bodies such as the European Emission Standard have set limits to the amount of sulfur in transportation fuel to safeguard the environment. Lately, the limit for clean fuel specification with respect to sulfur content is set to nearly zero ppm. This policy came at a time when crude oil experienced a large decline in price, in addition to increased sulfur content and daily fluctuations of crude density. Compliance with this tight regulation will mean that refineries are expected to either modify their hydrotreating unit, which is capital intensive, or adopt robust catalysts, through research, that can work in tandem with the existing conventional hydrotreating catalysts to reduce the sulfur level to the required limit. This urgent demand has once more drawn the attention of the scientific community. Since there has been a great stock of research outcomes with respect to catalysts for hydrodesulfurization application in recent times, our aim is to collect and review those recent articles on hydrodesulfurization catalyst design and development. The tutorial review is therefore intended to cover a basic hydrodesulfurization overview, followed by detailed discussions on the recent development in the choice of active phases, their supports, and synthesis strategies. The work is expected to guide researchers, especially beginners that are interested in refinery hydrotreatment, on the recent development in hydrodesulfurization catalyst design and development.

show abstract

Section: Active Phasesmentioning

confidence: 99%

Advanced Hydrodesulfurization Catalysts: A Review of Design and Synthesis

2019

View full text Add to dashboard Cite

show abstract

“…35,37,38 The higher HDS activities of niobium sulfides were further verified in several studies. 39,40 Niobium, as a dopant, improved the HDS of DBT and tetralin hydrogenation activities of an industrial NiMo/Al 2 O 3 catalyst. 41 Opposed to the strong effects of H 2 S on the performance of conventional HDS catalysts, the activity and durability of NbS 2 was found to be insensitive to H 2 S partial pressure.…”

Section: Introductionmentioning

confidence: 98%

“…49 NbS 3 consists of the same prismatic units, but the infinite-fiber Nb−S slabs are formed by sharing the triangular face of [NbS 6 ] prisms. 39 NbS 3 is more active in HDS than NbS 2 , which is likely due to the presence of anionic vacancies functioning as active sites; 35,36,39,50 however, generally, the thermal stabilities of trisulfide structures (NbS 3 , MoS 3 , WS 3 ) are low, and they transform to disulfides (NbS 2 , MoS 2 , WS 2 ) under hydrotreatment conditions, depending on reaction temperature, H 2 S partial pressure, and the textural properties of the material. 35,36 Despite the above-mentioned benefits of Nb-based catalysts, sulfidation of niobium oxides is not as facile as sulfidation of MoO 3 and WO 3 .…”

Section: Introductionmentioning

confidence: 99%

Promotion of Niobium Oxide Sulfidation by Copper and Its Effects on Hydrodesulfurization Catalysis

Mansouri

Semagina

2018

ACS Catal.

View full text Add to dashboard Cite

Niobium sulfide (NbS2) has shown a promising performance in versatile applications, but its formation from Nb oxide is thermodynamically limited, which hinders its usage. We predicted, based on thermodynamic calculations, and experimentally verified that the addition of copper (Cu) to niobium promotes Nb oxide sulfidation at practical temperatures. A series of bimetallic bulk NbCu structures at varying Cu/Nb molar ratios were synthesized via a coprecipitation technique. X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) results revealed that copper facilitated sulfidation and reduction of niobium oxide. The synthesized NbCu catalysts were evaluated in hydrodesulfurization (HDS) of dibenzothiophene (DBT) at 325 °C and 3 MPa. Copper promotes sulfidation but does not change the turnover frequency of surface NbS2 and behaves as a spectator. The optimal Cu/Nb molar ratio was found to be 0.3, below which there is not enough Cu to ensure maximum sulfidation and above which copper segregates to the catalyst surface and blocks NbS2 active sites. The weight-based sulfur-removal activity of the optimal catalyst was doubled in the presence of copper. This study demonstrates that the bimetallic Earth-abundant NbCu catalyst could be a promising candidate for hydrotreating catalysis. Since Cu-promoted NbS2 was determined to be more active than molybdenum sulfide per mass and surface area, the copper addition may be recommended for thermodynamically limited niobium oxide sulfidation to promote NbS2 formation as a potential alternative to MoS2 for a variety of emerging applications with transition-metal sulfides. The study also demonstrates that the concept of promotion in catalysis can be extended to the assisted increase of the number of active sites, with no effect on their performance during catalysis.

show abstract

“…Hydrolysis is a viable approach for CS 2 removal (Tong et al 1992;Zhao et al 2003;Wang et al 2013), CS 2 can be efficiently converted to COS and H 2 S at 300°C or higher in the presence of water. With the method of oxidation, CS 2 can be converted to S. Hydrogenation based on the formation of H 2 S (Allali et al 1995). However, the rigorous reaction conditions, including high temperature, high pressure and the existence of extraneous components, hindered its practical application.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of carbon disulfide on activated carbon modified by Cu and cobalt sulfonated phthalocyanine

Wang

Ning

et al. 2015

Adsorption

View full text Add to dashboard Cite

A series of adsorbents were studied for removal efficiency of carbon disulfide (CS 2 ) under micro-oxygen conditions. It was found that activated carbon modified by Cu and cobalt sulfonated phthalocyanine (CoSPc) denoted as ACCu-CoSPc showed significantly enhanced adsorption ability. Reaction temperature was found to be a key factor for adsorption, and 20°C seems to be optimal for CS 2 removal. Samples were analyzed by N 2 -BET, XRD, XPS, SEM-EDS and CO 2 -TPD. The characterization results demonstrated that large quantities of SO 4 2-anions were formed and adsorbed in the reaction process. SO 2 , CS 2 and COS were detected in the effluent gas generated from the temperature programmed desorption of ACCu-CoSPc-CS 2 . Therefore, it can be concluded that ACCu-CoSPc most likely acted as a catalyst in the adsorption/oxidation process on the surface of the impregnated sample. The generated sulfide and sulfur oxide can cover the active sites of adsorbents, resulting in pronounced reduction of adsorbent activity. Finally, the exhausted ACCu-CoSPc can be regenerated by thermal desorption.

show abstract

Carbon-Supported and Alumina-Supported Niobium Sulfide Catalysts

Cited by 28 publications

References 0 publications

Advanced Hydrodesulfurization Catalysts: A Review of Design and Synthesis

Advanced Hydrodesulfurization Catalysts: A Review of Design and Synthesis

Promotion of Niobium Oxide Sulfidation by Copper and Its Effects on Hydrodesulfurization Catalysis

Adsorption of carbon disulfide on activated carbon modified by Cu and cobalt sulfonated phthalocyanine

Contact Info

Product

Resources

About