HDS and HDN on SBA-supported RuS2 catalysts promoted by Pt and Ir

RuOx Quantum Dots Loaded on Graphdiyne for High-Performance Lithium-Sulfur Batteries

Here, a strategy to strengthen d-p orbital hybridization by fabricating π backbonding in the catalyst for efficient lithium polysulfides (LiPSs) conversion is reported. A special interface structure of RuOx quantum dots (QDs) anchored on graphdiyne (GDY) nanoboxes (RuOx QDs/GDY) is prepared to enable strong Ru-to-alkyne π backdonation, which effectively regulates the d-electron structures of Ru centers to promote the d-p orbital hybridization between the catalyst and LiPSs and significantly boosts the catalytic performance of RuOx QDs/GDY. The strong affinity with Li ions and fast Li-ion diffusion of RuOx QDs/GDY also enable ultrastable Li metal anodes. Thus, S@RuOx QDs/GDY cathodes exhibit excellent cycling performance under harsh conditions, and Li@RuOx QDs/GDY anodes show an ultralong cycling life over 8800 h without Li dendrite growth. Lithium-sulfur (Li-S) full cells with S@RuOx QDs/GDY cathodes and Li@RuOx QDs/GDY anodes can deliver an impressive areal capacity of 17.8 mA h cm-2 and good cycling stability under the practical conditions of low negative-to-positive electrode capacity (N/P) ratio (N/P = 1.4), lean electrolyte (E/S = 3 µL mg-1 ), and high S mass loading (15.4 mg cm-2 ).

DFT Insights into the Hydrodenitrogenation and Ring-Opening of Indole on an M (M = Ni, Pt, Ni–Pt) Slab Model

Density functional theory (DFT) calculation has been used to study the hydrodenitrogenation (HDN) and ring-opening of indole on an M (M = Ni, Pt, Ni–Pt) slab surface. The possible reaction pathway of indole hydrogenation has been investigated in order to reveal the bimetallic synergistic effects of an M slab surface. Compared to the mechanism of indole hydrogenation on an M slab surface, it was found that a PtNi(111) surface favors indole hydrogenation. According to the results of DFT calculation, it suggests that the bimetallic effect of the M surface plays an important role in indole hydrogenation.

DFT insights into the hydrodenitrogenation mechanism of quinoline catalyzed by different Ni-promoted MoS2 edge sites: Effect of the active phase morphology

Density functional theory calculations are performed to investigate the hydrodenitrogenation (HDN) mechanism of quinoline over different Ni-promoted MoS₂ edges. Based on the calculations, the hydrogenation and ring-opening reaction pathways are explored systematically, and the structure-activity relationship of different active sites is discussed in detail. In the hydrogenation reaction process, the 100% Ni-promoted M-edge and 50% Ni-promoted S-edge are favorable for the formations of 5,6,7,8-tetrahydroquinoline and 1,2,3,4-tetrahydroquinoline, respectively. Furthermore, the 100% Ni-promoted M-edge is more preferable for the generation of decahydroquinoline rather than the 50% Ni-promoted S-edge. In the denitrogenation reaction step, the 100% Ni-promoted M-edge is beneficial for the formation of ortho-propylaniline and 2-propylcyclohexylamine, while 50% Ni-promoted S-edge is only conducive to the formation of 2-propylcyclohexylamine. Therefore, it can be concluded that both hydrogenation derivatives and denitrogenation products exhibit strong dependence on the active phase morphology, meaning that multiple active sites can be involved in one catalytic HDN cycle.

Hierarchical Hybrid Supports and Synthesis Strategies for Hydrodesulfurization of Recalcitrance Organosulfur Compounds

It is undisputed that there is a paradigm shift in the global trend of crude oil towards being more sour and heavier than usual light sources. Consequently, the hydrotreating activity becomes a bottleneck with high content of S, N, metals and other impurities than expected. On the other hand, the price of petroleum products lately witnessed instability and fell to the lowest average price (<USD 20) in recent times. In the same vein, the regulation to control the emission of toxic compounds in the atmosphere become stricter as promulgated by various policymakers. In this sense, robust hydrotreating catalysts with characteristics efficient catalytic activity, selectivity and stability are highly desirable. Recently, different approaches have been used to improve and cushion the unprecedented effect emanated from economic, social and environmental challenges posed by heavy and sour crude sources, price instability of the refined products and regulation to lower the sulfur to minimum level or zero parts per millions (ppm). Importantly, the role of support in catalysis cannot be over emphasized, whilst the surface area and porosity, mechanical and thermal stability, dispersion of active metals, acidity/basicity have been greatly improved, the increased activity, stability and selectivity has been observed significantly. In this review, hybrid supports based on aluminosilicates (zeolitic types) and other notable supports from recent literatures were explored and discussed for Ni(Co)Mo(W) supported catalysts for hydrodesulfurization (HDS) activity of heavy organosulfur molecules. The emphasis on the hybrid supports' varied characteristics for HDS of organosulfur molecules, where there are necessities for fast diffusion of reactants and products, better dispersion of MoS₂ crystallites, high surface area and pore volume, and increased acidity of the catalysts are greatly emphasized. Furthermore, the progress made so far on different HDS active phases viz. noble metals, metal phosphides, intermetallic silicides, carbides and iron-zinc are highlighted in this write-up, irrespective of the support composition in the supported catalysts formulations. The need for application of predictive tools, like machine learning (ML) in the design and development of HDS catalysts, and performance evaluation of HDS activity towards achieving better catalytic operation was briefly highlighted. Finally, the review will serve as a summary of scientific efforts in this regards and bridge a gap for the newcomers to investigate the topic in a better way through proper selection and efficient catalysts design.

Enhanced HDO activity of Ni2P promoted with noble metals

A series of bimetallic Ni₂P–noble metal (Pt, Rh, Ir or Ru) catalysts supported on commercial silica were prepared in order to evaluate the promoter effect of noble metals on the activity and stability of these catalysts in the hydrodeoxygenation (HDO) of dibenzofuran (DBF).

Preparation and characterization of NiW supported on Al-modified MCM-48 catalyst and its high hydrodenitrogenation activity and stability

Al-containing MCM-48 with different Si/Al ratios and aluminum free MCM-48 materials were successfully prepared with CTAB and P123 as a co-template.