CO hydrogenation reaction on sulfided molybdenum catalysts

Shi, Xue-Rong; Jiao, Haijun; Hermann, Klaus; Wang, Jianguo

doi:10.1016/j.molcata.2009.06.025

Cited by 53 publications

(26 citation statements)

References 67 publications

(65 reference statements)

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“…The methylene intermediate prefers to adsorbed at the top site with the adsorption energy of −5.77 eV on fcc-Mo 2 C (1 0 0) but adsorbed at the bridge site with −5.46 eV on hcp-Mo 2 C (1 0 1), which is a little larger than that on MoS 2 surfaces (−4.41 eV) obtained by Shi et al [39]. The bonding capability of C atom involved in CH 2 to surface is very strong, which is consistent with the short C Mo bond lengths (2.22Å on fcc-Mo 2 C (1 0 0), 2.04 and 2.06Å on hcp-Mo 2 C (1 0 1)).…”

Section: Methylene (Ch 2 ) Adsorptionmentioning

confidence: 60%

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

Wang

Zheng

2013

Applied Surface Science

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Section: Methylene (Ch 2 ) Adsorptionmentioning

confidence: 60%

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

Wang

Zheng

2013

Applied Surface Science

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“…As shown in Figure , TS3 was ∼0.24 eV lower in energy than TS3′, implying that the formation of CH 2 O was favored over that of CHOH, despite intermediate M5′ being more thermodynamically stable than M5 by ∼0.17 eV. Moreover, Shi et al claimed that M6 ( E (ads) = −0.85 eV, CO double bond) corresponded to the most stable structure of adsorbed CH 2 O when compared with M5 ( E (ads) = −0.57 eV CO single bond). Thus, the obtained energy profile indicated that the formation of M6 from M4 involves the formation of intermediate M5, with the energy barrier of the M5 → M6 transformation equaling 0.32 eV.…”

Section: Resultsmentioning

confidence: 98%

“…According to Shi et al, CO methanation on Mo edges should be studied through the creation of at least one S vacancy. As such, the stable CO adsorbate configurations over different surfaces are presented in Table .…”

Section: Resultsmentioning

confidence: 99%

DFT study into the reaction mechanism of CO methanation over pure MoS₂

Zhang

Wang

et al. 2018

Int J of Quantum Chemistry

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Mo-based catalysts are commonly used in the direct methanation of CO; however, no integrated mechanism has been proposed due to limits in characterizing the nano-sized active structures of MoS 2 . Thus, we report our investigation into the mechanism of CO methanation over pure MoS 2 through density functional theory simulations, considering that only MoS 2 edge sites exhibit catalytic activity. Simulations revealed the presence of (010) and (110) surfaces on the MoS 2 edges.Both surfaces are reconstructed by the redistribution of surface sulfur atoms upon exposure to H 2 /H 2 S, and after sulfur coverage redistribution, S vacancies are generated for CO hydrogenation.The reaction mechanisms on both surfaces are discussed, with the S-edge being better suited to CO methanation than Mo-edge on the (010) surface. The rate-controlling step differs between surfaces, and corresponds to the initial activation reaction, which was achieved more easily on the (110) surface. K E Y W O R D S density functional theory calculation, first principles methods, heterogeneous catalysis, Mo-based catalyst, sulfur-resistant methanation | I N TR ODU C TI ONThe extensive use of natural gas to reduce the pollution caused by coal combustion has resulted in an increased global demand for this fuel. To meet such a demand, a novel coal gasification and syngas methanation technology has been adopted in China and other coal-rich countries to produce substitute natural gas, [1] thereby rendering the mechanistic characterization of methanation an important research area. [2] In this context, the sulfur-resistant nature of Mo-based catalysts [3,4] allows their use in the direct methanation of syngas, bypassing the desulfurization and water-gas shift reactions, [5,6] but requiring further experimental and theoretical investigations with regards to their corresponding reaction mechanisms.The activities and selectivities of Mo-based catalysts have been extensively studied to date, [7][8][9][10] with MoS 2 being currently recognized as the active phase of Mo-based catalysts. [11][12][13] However, despite various of experimental techniques (ie, Transition electron microscopy (TEM), [14,15] Xray photoelectron spectroscopy (XPS), [16] laser Raman spectroscopy, [17] extended X-ray absorption fine structure (EXAFS), [18] and IR spectroscopy [19] ) involved in characterizing the crystal structure and active phase roughly, it still has difficulty in determining active sites of nano-crystals presenting active MoS 2 moieties, which has led to a lack of integrated and detailed mechanistic investigations into the sulfur-resistant methanation reaction from a microscopic viewpoint. To circumvent the difficulties of experimental characterization, density functional theory (DFT) simulations [20] can be used to probe the reaction mechanism by determining the active site(s) and possible intermediates involved in the process, and subsequently searching for a suitable reaction path to calculate the reaction energy barrier and elucidate the rate-controlling step.Similar ...

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“…However,t here are other factors such as spin states and coordination geometries of the enzyme cofactor that mayb ei mportant and will not be captured by these heterogeneous surfaces. [56,57] Interesting activity of TMSs have been mainly reported for oxygen depolarized cathode applications, [58] hydrodesulfurization, [59][60][61][62] HER, [63][64][65][66][67] CO hydrogenation, [68] and CO 2 reduction reaction. [69,70] However,t ot he best of our knowledge, there is no investigation reported in literature regarding the catalytic activity of these materials for electrochemical NRR to ammonia at ambient conditions.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic Nitrogen Fixation Catalyzed by Transition Metal Sulfide Surfaces in an Electrolytic Cell

2019

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The nitrogen reduction reaction was investigated on the surfaces of 18 different stable transition metal sulfides using density functional theory calculations. YS, ScS, and ZrS were modeled in the rocksalt structure with the (1 0 0) facet; TiS, VS, CrS, NbS, NiS, and FeS in NiAs‐type structure with the (1 1 1) facet; and MnS2, CoS2, IrS2, CuS2, OsS2, FeS2, RuS2, RhS2, and NiS2 in pyrite structure for both the (1 0 0) and (1 1 1) orientations. As the first step towards determination of sulfides that are less prone to hydrogen evolution, the competition between adsorption of NNH and H (for the associative mechanism), and between adsorption of N and H (for the dissociative mechanism) on these surfaces was considered. The catalytic activity through both the associative and dissociative mechanisms was explored and the overpotential required for electrochemical ammonia formation is reported. The scaling relations and volcano plots were constructed with free energy of adsorption of NNH or N on the surface as the descriptor. RuS2 was observed as the most active sulfide that could catalyze nitrogen reduction to ammonia at potentials around −0.3 V through the associative mechanism. NbS, CrS, TiS, and VS are also promising candidates for both the associative and dissociative mechanisms with overpotentials for nitrogen reduction around 0.7–1.1 V.

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CO hydrogenation reaction on sulfided molybdenum catalysts

Cited by 53 publications

References 67 publications

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

DFT study into the reaction mechanism of CO methanation over pure MoS₂

Biomimetic Nitrogen Fixation Catalyzed by Transition Metal Sulfide Surfaces in an Electrolytic Cell

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CO hydrogenation reaction on sulfided molybdenum catalysts

Cited by 53 publications

References 67 publications

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

Structure-sensitivity of ethane hydrogenolysis over molybdenum carbides: A density functional theory study

DFT study into the reaction mechanism of CO methanation over pure MoS2

Biomimetic Nitrogen Fixation Catalyzed by Transition Metal Sulfide Surfaces in an Electrolytic Cell

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DFT study into the reaction mechanism of CO methanation over pure MoS₂