Effects of carbon on the sulfidation and hydrodesulfurization of CoMo hydrating catalysts

Ge, Hui; Li, Xuekuan; Qin, Zhangfeng; Liang, Feixue; Wang, Jianguo

doi:10.1007/s11814-009-0098-6

Cited by 10 publications

(11 citation statements)

References 31 publications

(26 reference statements)

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“…Part IV, however, exhibits stable weight. The total weight loss in Part III and Part IV is ≈37.4 wt %, less than the theoretical value of ethylenediamine content in Co(en) 3 MoO 4 (i.e., 45.1 wt %), indicating the presence of residues (e.g., C‐ and N‐containing species), which are formed during the subsequent pyrolysis of Co(en)MoO 4 overlapping with the deamination process . This is confirmed by elemental analysis of the calcined CoMo‐Ar sample, where 2.75 wt % C and 3.97wt % N species were detected.…”

Section: Resultsmentioning

confidence: 98%

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Duan

Yan

et al. 2016

ChemCatChem

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To elucidate the effect of textural and chemical properties of catalysts and to discriminate the active phase are fundamental issues in heterogeneous catalysis, but they are often complicated by the nature of support adding a new dimension. In this work, metal amine metallate (Co(en)3MoO4) precursor was directly treated by calcination and prenitridation to understand these two issues in Co‐Mo catalyzed ammonia decomposition. The calcination atmosphere (i.e., Ar and Air) is found to remarkably affect the textural and chemical properties of catalysts, and air atmosphere is favorable for higher stable reactivity despite incomplete nitridation of the catalyst. Further prenitridation of the sample from the calcination of Co(en)3MoO4 under air gives rise to higher catalytic activity, and Co3Mo3N is suggested as the dominant active phase of Co‐Mo catalysts. The insights revealed here shed new light on the design of Co‐Mo catalysts for ammonia decomposition.

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Section: Resultsmentioning

confidence: 98%

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Duan

Yan

et al. 2016

ChemCatChem

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“…They proposed that the observed positive effect is due to the active particles isolating from each other by carbon deposits thus maintaining a high dispersion. 20 Addition of chelating agents in the catalyst preparation is an effective way to improve catalytic activity. 18,19 CoMo/Al 2 O 3 catalyst with addition of Ethylenediamine (EN) and with N 2 heat-treating detected two carbon species; one covering the surface of active phase and another inserting between active particles and alumina, showing opposite effects on the HDS performance.…”

Section: Introductionmentioning

confidence: 99%

Carbonization of Ethylenediamine Coimpregnated CoMo/Al₂O₃ Catalysts Sulfided by Organic Sulfiding Agent

Xiao

Ramos

et al. 2014

ACS Catal.

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Co-impregnating binary Cobalt/Molybdenum/Alumina (CoMo/Al 2 O 3 ) catalyst with addition of ethylenediamine was studied for carbonization, sulfidation and hydrodesulfurization using experimental methods. In order to understand the mechanism of carbonization of active phases, theoretical CoMo/Carbon models were produced using density functional theory (DFT) methods. Results from carbonization of the organic component indicate that the formation of support-like carbon species provoke dispersion of active particles and reduce interaction with support at the active sites (Co, Mo), thus enhancing the HDS activity. Geometrical optimization by DFT shows that a carbide-like Co-Mo-C structures are more stable, which can be formed by a simultaneous carburization and sulfidation at unsaturated S or Mo edge of (Co)MoS x slab with CH 3 SSCH 3 as both carbon and sulfur source.Until now, the issues concerning the carbonation of HDS catalysts are still in debate. For systematically and explicitly elucidating the roles played by carbon species, we designed a research plot. We firstly identified the carbon species on HDS catalyst, investigated the formation mechanism of each carbon species, and then illustrated the effect of these carbon species on the HDS activity. In this work, experimentally, CoMo catalysts were prepared with addition of EN, and then sulfided with organic agents (thiophene and DMDS). We focus our attention to the carbon species. In order to correlate experimental results a series of computer assisted DFT calculations were performed, investigating the carburization at the "Co-Mo-S" active sites at the atomic level. Experimental and computational details Catalyst preparationThe catalysts were prepared by impregnating γ-Al 2 O 3 with NH 3 aqueous solution of Co(NO 3 ) 2 ·6H 2 O, (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and EN, followed by drying at 110 o C for 12 h. The catalysts with the EN/Co molar ratio of 1 and 2 were denoted as CoMo(EN1) and CoMo(EN2) respectively. Comparison catalyst was prepared by calcining CoMo(EN1) under air at 450 o C for 4 h to remove EN; it was represented as CoMo. The loadings of CoO and MoO 3 for all catalysts (after calcinations) were 3.2 and 16 wt%, respectively. Catalyst sulfidation and HDS testThe sulfidation and HDS tests were carried in a fixed bed tubular flow reactor with an inner

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“…The total weightl oss in Part III and Part IV is % 37.4 wt %, less than the theoretical value of ethylenediamine content in Co(en) 3 MoO 4 (i.e.,4 5.1 wt %), indicating the presence of residues (e.g.,C -a nd N-containings pecies), whicha re formed duringt he subsequent pyrolysis of Co(en)MoO 4 overlapping with the deaminationp rocess. [13] This is confirmed by elemen- ChemCatChem 2016, 8,938 -945 www.chemcatchem.org tal analysiso ft he calcined CoMo-Ar sample, where 2.75 wt %C and 3.97wt %Nspecies were detected. In contrast, under the air atmosphere,P art III and Part IV exhibit the weight loss of % 25.5 wt %a nd that of % 20.4 wt %, respectively,c orresponding to the deamination and/oro xidation reactionp rocess.…”

Section: Influence Of Calcination Atmospherementioning

confidence: 60%

ChemInform Abstract: Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase.

Duan

Yan

et al. 2016

ChemInform

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Effects of carbon on the sulfidation and hydrodesulfurization of CoMo hydrating catalysts

Cited by 10 publications

References 31 publications

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Carbonization of Ethylenediamine Coimpregnated CoMo/Al₂O₃ Catalysts Sulfided by Organic Sulfiding Agent

ChemInform Abstract: Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase.

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Effects of carbon on the sulfidation and hydrodesulfurization of CoMo hydrating catalysts

Cited by 10 publications

References 31 publications

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase

Carbonization of Ethylenediamine Coimpregnated CoMo/Al2O3 Catalysts Sulfided by Organic Sulfiding Agent

ChemInform Abstract: Understanding Co‐Mo Catalyzed Ammonia Decomposition: Influence of Calcination Atmosphere and Identification of Active Phase.

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Carbonization of Ethylenediamine Coimpregnated CoMo/Al₂O₃ Catalysts Sulfided by Organic Sulfiding Agent