Catalysis by sulfides: Advanced IR/CO spectroscopy for the identification of the most active sites in hydrodesulfurization reactions

Oliviero, Laetitia; Travert, Arnaud; Garcia, Elizabeth Dominguez; Chen, Jianjun; Maugé, Françoise

doi:10.1016/j.jcat.2021.02.018

Cited by 15 publications

(11 citation statements)

References 41 publications

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“…The former adsorption takes place at the Mo-edge sites of MoS 2 particles (six-coordinated Mo atoms with 50% S-coverage), while the latter takes place at the S-edge sites (100% S-coverage). 62 …”

Section: Resultsmentioning

confidence: 99%

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Wang

Ning

et al. 2023

ACS Omega

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A novel impregnation−deposition method was applied to prepare presulfided MoS 2 /Al 2 O 3 catalysts with large surface areas for the application of hydrodesulfurization (HDS). The synthesized catalysts were characterized systematically, and their catalytic performances were evaluated by the HDS of dibenzothiophene (DBT). It is found that the impregnation−deposition method improves the surface area of the synthesized catalysts by eliminating the micropores of the alumina support and adding mesostructured MoS 2 particles within the support. Moreover, this method enhances the reducibility of the sulfided Mo species, as characterized by temperature-programed reduction (TPR) and X-ray photoelectron spectroscopy. Compared to the impregnation method, the impregnation−deposition method leads to the formation of more active sites as proved by TPR and CO-Fouriertransform infrared analyses. Hence, the reaction conversion rates and the hydrogenation/direct-desulfurization ratios of the DBT on the catalysts synthesized by the impregnation−deposition method are 1.3 times and 1.5 times as high as those of the catalysts made by the conventional impregnation method, respectively.

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Section: Resultsmentioning

confidence: 99%

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Wang

Ning

et al. 2023

ACS Omega

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“…CO has been successfully used as a probe for Lewis acid sites (LAS) on TMS. 26 , 50 − 52 In this case, CO appears to be an ideal probe. First, as long as CO molecules are not aligned, the wavenumbers of IR bands of CO adsorbed on LAS can be directly related to the electronic properties of the metal sites.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, we turn to an indirect method to characterize the location and concentration of adsorbed hydrogen, using CO as a probe molecule. CO has been successfully used as a probe for Lewis acid sites (LAS) on TMS. ,− In this case, CO appears to be an ideal probe. First, as long as CO molecules are not aligned, the wavenumbers of IR bands of CO adsorbed on LAS can be directly related to the electronic properties of the metal sites.…”

Section: Resultsmentioning

confidence: 99%

“…Most reactions studied on these catalysts involve H 2 as a reactant on sites that have been characterized by microscopy, , spectroscopy, , and adsorption of molecular probes, , guided and aided by theory. − The efforts have led to significantly improved catalytic properties, as well as to better atomistic understanding of local structures, and detailed mechanisms for hydrogenation/hydrogenolysis reactions. While the link between these catalysts and enzymes with sulfide based active sites seems intuitive, clear analogies have not been substantiated. ,, …”

Section: Introductionmentioning

confidence: 99%

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Di- and Tetrameric Molybdenum Sulfide Clusters Activate and Stabilize Dihydrogen as Hydrides

Khare

Weindl

Jentys

et al. 2022

JACS Au

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NaY zeolite-encapsulated dimeric (Mo 2 S 4 ) and tetrameric (Mo 4 S 4 ) molybdenum sulfide clusters stabilize hydrogen as hydride binding to Mo atoms. Density functional theory (DFT) calculations and adsorption measurements suggest that stabilization of hydrogen as sulfhydryl (SH) groups, as typical for layered MoS 2 , is thermodynamically disfavored. Competitive adsorption of H 2 and ethene on Mo was probed by quantifying adsorbed CO on partly hydrogen and/or ethene covered samples with IR spectroscopy. During hydrogenation, experiment and theory suggest that Mo is covered predominately with ethene and sparsely with hydride. DFT calculations further predict that, under reaction conditions, each Mo x S y cluster can activate only one H 2 , suggesting that the entire cluster (irrespective of its nuclearity) acts as one active site for hydrogenation. The nearly identical turnover frequencies (24.7 ± 3.3 mol ethane ·h –1 ·mol cluster –1 ), apparent activation energies (31–32 kJ·mol –1 ), and reaction orders (∼0.5 in ethene and ∼1.0 in H 2 ) show that the active sites in both clusters are catalytically indistinguishable.

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“…Note also that the scale in the Y-axis is different for Mo (0−200 ppb), Co (0−2 ppb), and Pt (0−0.02 ppb) elements. This difference suggests that most of dissolved Mo arise from oxysulfides, which were not entirely sulfidated during the sulfidation step (the presence of oxysulfides was already noticed in our former work; see ref 30). After these first potential cycles, the quantities of dissolved Mo, Pt, or Co decreased, approaching 1, <0.5, and <0.01 ppb, respectively.…”

Section: Hr Stem-haadf Characterization Of Mos 2 -Based Catalystsmentioning

confidence: 99%

Direct Evidence of the Role of Co or Pt, Co Single-Atom Promoters on the Performance of MoS₂ Nanoclusters for the Hydrogen Evolution Reaction

et al. 2023

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Developing alternatives to platinum (Pt) and iridium (Ir) in proton-exchange membrane water electrolyzers is crucial on the way to viable energy provision schemes. However, although it seems difficult to substitute Ir, alternatives exist for Pt at the proton-exchange membrane water electrolyzer cathode. Here, we report on the synthesis and the characterization of efficient and durable hydrogen evolution reaction (HER) nanocatalysts based on MoS 2 supported on high-surface-area carbon. Citric acid was used as a chelating agent to control the size of the MoS 2 crystallites (1.4 nm) and thus the density of active sites (slab edges). Inspired by successful approaches in catalysis for hydrodesulfurization reactions, conventional 2H MoS 2 was sequentially doped with cobalt (Co) and then with 1 wt % of Pt. Overpotentials of 188, 140, and 118 mV at 10 mA cm −2 are reported for MoS 2 /C, Co− MoS 2 /C, and Pt 1% −CoMoS 2 /C, respectively. This result is attributed to the weakening of the H ads binding energy of the promoted MoS 2 -edge active sites (because the promoting atoms are mostly located at the edges). Associated with small-metal dissolution rates (monitored in situ, during the HER), our findings demonstrate that metal promotion (doping) is a promising route to replace Pt with earth-abundant elements in acidic water electrolyzers.

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Catalysis by sulfides: Advanced IR/CO spectroscopy for the identification of the most active sites in hydrodesulfurization reactions

Cited by 15 publications

References 41 publications

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Di- and Tetrameric Molybdenum Sulfide Clusters Activate and Stabilize Dihydrogen as Hydrides

Direct Evidence of the Role of Co or Pt, Co Single-Atom Promoters on the Performance of MoS₂ Nanoclusters for the Hydrogen Evolution Reaction

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Catalysis by sulfides: Advanced IR/CO spectroscopy for the identification of the most active sites in hydrodesulfurization reactions

Cited by 15 publications

References 41 publications

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS2/Al2O3 Catalyst and Its Application in Hydrodesulfurization

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS2/Al2O3 Catalyst and Its Application in Hydrodesulfurization

Di- and Tetrameric Molybdenum Sulfide Clusters Activate and Stabilize Dihydrogen as Hydrides

Direct Evidence of the Role of Co or Pt, Co Single-Atom Promoters on the Performance of MoS2 Nanoclusters for the Hydrogen Evolution Reaction

Contact Info

Product

Resources

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Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Novel Impregnation–Deposition Method to Synthesize a Presulfided MoS₂/Al₂O₃ Catalyst and Its Application in Hydrodesulfurization

Direct Evidence of the Role of Co or Pt, Co Single-Atom Promoters on the Performance of MoS₂ Nanoclusters for the Hydrogen Evolution Reaction