New insight into the support effect on HDS catalysts: evidence for the role of Mo-support interaction on the MoS2 slab morphology

Garcia, Elizabeth Dominguez; Chen, Jianjun; Oliviero, Erwan; Oliviero, Laetitia; Maugé, Françoise

doi:10.1016/j.apcatb.2019.117975

Cited by 71 publications

(23 citation statements)

References 44 publications

(62 reference statements)

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“…The CoMoS edge sites of these catalysts were in-situ characterized by lowtemperature CO adsorption followed by IR spectroscopy [12,19,21,22]. First, the dried catalytic precursor in oxidic form was grounded and pressed into a self-supported wafer (10 mg for a disc of 2.01 cm 2 ) precisely weighted and positioned into a quartz IR cell with CaF2 windows.…”

Section: Low-temperature Co Adsorption Followed By Ir Characterization (Ir/co)mentioning

confidence: 99%

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

et al. 2021

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In this work, we present atomic-scale images of Co promoted MoS2 slabs supported on γ-Al2O3 obtained by High Resolution Scanning Transmission Electron Microscopy equipped with High Angular Annular Dark Field detector (HR STEM-HAADF). These images allow to study the effect of citric acid (CA) addition during preparation, on the slab length and its stability during thiophene hydrodesulfurization (HDS) reaction.Thus, the observations, obtained for sulfide catalysts prepared without or with citric acid as chelating agent, evidenced strong decrease in size of the CoMoS nano-slabs as detected indirectly by the adsorption of CO followed by Infrared spectroscopy (IR/CO). Quantitative dispersion values were calculated from the images taking into account the true shape of the particles instead of the classical hexagonal shape 2 hypothesis. Characterization of the used catalyst shows that these nanoclusters are stable under model thiophene HDS reaction.. Such observations allow a better understanding of the effect of chelating agent addition on promoted MoS2 samples in order to explain their catalytic activity.

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Section: Low-temperature Co Adsorption Followed By Ir Characterization (Ir/co)mentioning

confidence: 99%

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

et al. 2021

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“…Two-dimensional transition metal dichalcogenides, such as metal nitrides, [1,2] sulfides, [3][4][5] carbides, [2,6] selenides, [7][8][9] and phosphides, [10,11] are abundant, inexpensive, and potentially useful. Among them, MoS 2 is an excellent catalyst, and was initially used in hydrodesulfurization, [12,13] which involves similar reversible hydrogen desorption to the hydrogen evolution reaction (HER). Therefore, it was speculated that MoS 2 might be a suitable electrocatalyst for the HER.…”

Section: Introductionmentioning

confidence: 99%

Defects Enhance the Electrocatalytic Hydrogen Evolution Properties of MoS₂‐based Materials

Cheng

Song

et al. 2020

Chemistry An Asian Journal

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MoS 2 have recently emerged as alternatives to noble metals as electrocatalysts for the hydrogen evolution reaction (HER) owing to their abundance and low cost. Considering the shortcomings of MoS 2 , including insufficient active sites, inert basal plane, and poor conductivity, the electrocatalytic hydrogen evolution properties of MoS 2 can be improved in three ways: activating the inert basal plane to improve intrinsic activity, increasing active edge sites, and improving the conductivity. Defects can adjust the surface electronic structure of the crystal to bring the hydrogen adsorption free energy closer to zero. Therefore, current research has mainly used S-vacancies to activate the inert basal surface of MoS 2 ; used edge defects to increase the number of active sites; and used defective conductive carbon supports to improve the conductivity of MoS 2-based catalysts. This review introduces researches on improving the performance of MoS 2 for HER by considering the purpose, characterization, and preparation of defects.

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“…Further, determination of the molar attenuation coefficients of ν(CO) band characteristics of the M‐edge and S‐edge sites allowed quantification of these two edges and thus assessment of the morphology of MoS 2 slabs . It was thus possible to demonstrate that the MoS 2 morphology (expressed by S edge /M edge ratio) varies with the preparation parameters (metal loading, chelating agent addition, support nature) and the sulfidation conditions . Recent observations of the sulfide catalysts by STEM HAADF confirmed the morphology of the MoS 2 slabs deduced from the spectroscopic analysis .…”

Section: Introductionmentioning

confidence: 99%

Structure and Quantification of Edge Sites of WS₂/Al₂O₃ Catalysts Coupling IR/CO Spectroscopy and DFT Calculations

et al. 2020

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IR spectroscopy of CO adsorption (IR/CO) and Density Functional Theory (DFT) calculations on sulfide W/Al2O3 catalyst were investigated for an insight into the sulfide edge sites. Parallel between experimental and theoretical results allow to assign the ν(CO) bands at 2121 and 2066 cm−1 to CO adsorption on M‐ and S‐edge sites of WS2 phase, respectively. Through a careful analysis of CO spectra on well‐selected W catalysts, the molar attenuation coefficients for CO adsorbed on the two exposed edges could be determined. This allowed the morphology of WS2 slabs to be calculated. This work shows that increasing the W loading (6–20 wt% W) changes the slab morphology from an almost pure triangle exhibiting mostly M‐edge to a truncated triangle. On W as well as on Mo sulfide catalysts, IR spectroscopy and DFT calculation show that CO adsorption allows to account for M‐ and S‐edge sites, and thus of the morphology of sulfide slabs. It was shown that increasing the W loading shifts the slab morphology from a triangle exposing predominantly M‐edge towards a more hexagonal shape. For close to monolayer coverage of alumina, Mo and W sulfide slabs present similar shape i. e. truncated triangle. However, edge sites of WS2 slabs clearly exhibit greater stability under H2 atmosphere than Mo sulfided ones.

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New insight into the support effect on HDS catalysts: evidence for the role of Mo-support interaction on the MoS2 slab morphology

Cited by 71 publications

References 44 publications

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

Defects Enhance the Electrocatalytic Hydrogen Evolution Properties of MoS₂‐based Materials

Structure and Quantification of Edge Sites of WS₂/Al₂O₃ Catalysts Coupling IR/CO Spectroscopy and DFT Calculations

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New insight into the support effect on HDS catalysts: evidence for the role of Mo-support interaction on the MoS2 slab morphology

Cited by 71 publications

References 44 publications

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

Formation and stability of CoMoS nanoclusters by the addition of citric acid: A study by high resolution STEM-HAADF microscopy

Defects Enhance the Electrocatalytic Hydrogen Evolution Properties of MoS2‐based Materials

Structure and Quantification of Edge Sites of WS2/Al2O3 Catalysts Coupling IR/CO Spectroscopy and DFT Calculations

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Defects Enhance the Electrocatalytic Hydrogen Evolution Properties of MoS₂‐based Materials

Structure and Quantification of Edge Sites of WS₂/Al₂O₃ Catalysts Coupling IR/CO Spectroscopy and DFT Calculations