Tungsten carbides as selective deoxygenation catalysts: experimental and computational studies of converting C3 oxygenates to propene

Ren, Hui; Chen, Ying; Huang, Yangen; Wen, Ding; Vlachos, Dionisios G.; Chen, Jingguang G.

doi:10.1039/c3gc41256c

Cited by 73 publications

(68 citation statements)

References 43 publications

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“…They reported that the Mo-terminated Mo 2 C (0 0 1) surface behaved similarly to Ru/Rh with regard to carbon reactivity, but acts more like Mo/W with regard to oxygen reactivity. These results are consistent with recent work exploring the deoxygenation of biomass-derived intermediates over early transition metal carbides, which demonstrated that these materials favor C-O bond cleavage due to their strong affinity for oxygen [23][24][25]. Medford et al also reported that the activation energy for CO dissociation over Mo 2 C was relatively low (1.43 eV), and that the hydrogenation of CO led to significantly lower CO dissociation barriers [22].…”

Section: Introductionsupporting

confidence: 88%

Fischer–Tropsch synthesis over early transition metal carbides and nitrides: CO activation and chain growth

Schaidle

Thompson

2015

Journal of Catalysis

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a b s t r a c tA series of transition metal carbide and nitride catalysts (Mo 2 C, Mo 2 N, W 2 C, W 2 N, VC, VN, NbC, and NbN) were prepared and evaluated for Fischer-Tropsch synthesis. The activity trend was Mo 2 C $ W 2 C $ VN $ NbN > Mo 2 N $ W 2 N ) VC $ NbC, with carbides and nitrides of the same parent metal exhibiting significantly different turnover frequencies (TOF). For example, the Mo 2 C catalyst exhibited a TOF of 0.36 s À1 at 300°C whereas the TOF for the Mo 2 N catalyst was 0.04 s À1 . The carbides and nitrides favored light hydrocarbons (C 1 -C 4 ) exhibiting a values between 0.31 and 0.43 at 290°C, and were active for the water-gas shift reaction. Results from temperature programmed desorption and reaction indicated that both the Mo 2 N and Mo 2 C catalysts are capable of direct (without H 2 assistance) CO dissociation; however, the activation barrier is much higher over Mo 2 N than Mo 2 C. The results also indicate that C-C coupling over the Mo 2 C surface was facilitated by molecularly adsorbed CO (without H 2 pre-adsorption), suggesting the primary pathway to C 2+ hydrocarbons was through the oxygenate mechanism.

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Section: Introductionsupporting

confidence: 88%

Fischer–Tropsch synthesis over early transition metal carbides and nitrides: CO activation and chain growth

Schaidle

Thompson

2015

Journal of Catalysis

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“…137,[139][140][141] The ability of tungsten and molybdenum carbides to remove heteroatoms suggests they could be promising catalysts for biomass deoxygenation. For example, through DFT calculations as well as surface science and gas-phase reactor studies using propanol and propanal as reactants, WC was shown to activate C-O bonds but not C-C; the dominant product formed was propene.…”

Section: Carbides Nitrides and Phosphidesmentioning

confidence: 99%

Bifunctional Catalysts for Upgrading of Biomass-Derived Oxygenates: A Review

2016

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Deoxygenation is an important reaction in the conversion of biomass-derived oxygenates to fuels and chemicals. A key route for biomass refining involves the production of pyrolysis oil through rapid heating of the raw biomass feedstock. Pyrolysis oil as produced is highly oxygenated, so the feasibility of this approach depends in large part on the ability to selectively deoxygenate pyrolysis oil components to create a stream of high-value finished products. Identification of catalytic materials that are active and selective for deoxygenation of pyrolysis oil components has therefore represented a major research area. One catalyst is rarely capable of performing the different types of elementary reaction steps required to deoxygenate biomass-derived compounds. For this reason, considerable attention has been placed on bifunctional catalysts, where two different active materials are used to provide catalytic sites for diverse reaction steps. Here, we review recent trends in the development of catalysts, with a focus on catalysts for which a bifunctional effect has been proposed. We summarize recent studies of hydrodeoxygenation (HDO) of pyrolysis oil and model compounds for a range of materials, including supported metal and bimetallic catalysts as well as transition metal oxides, sulfides, carbides, nitrides, and phosphides. Particular emphasis is placed on how catalyst structure can be related to performance via molecular-level mechanisms. These studies demonstrate the importance of catalyst bifunctionality, with each class of materials requiring hydrogenation and C-O scission sites to perform HDO at reasonable rates. OH R' RO Phenolics O OH R Acids O R Ketones and Aldehydes R" R'

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“…It has been demonstrated that the catalytic properties of these cheaper metal carbides are comparable to the catalytic properties of the more expensive Pt-groups metals [19][20][21][22]. In the case of dehydrogenation, hydrogenation and hydrogenolysis, which involve a transformation of hydrocarbons' C-H bonds, activities of these metal carbides are similar or better than the activities of Pt-group metals [19,[23][24][25]. For example, W-carbides can substitute Pt in hydro-isomerization reactions [26][27][28], if the correct pretreatment has been applied.…”

Section: Introductionmentioning

confidence: 95%

Metal Carbides for Biomass Valorization

Chan‐Thaw

Villa

2018

Applied Sciences

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Transition metal carbides have been utilized as an alternative catalyst to expensive noble metals for the conversion of biomass. Tungsten and molybdenum carbides have been shown to be effective catalysts for hydrogenation, hydrodeoxygenation and isomerization reactions. The satisfactory activities of these metal carbides and their low costs, compared with noble metals, make them appealing alternatives and worthy of further investigation. In this review, we succinctly describe common synthesis techniques, including temperature-programmed reaction and carbothermal hydrogen reduction, utilized to prepare metal carbides used for biomass transformation. Attention will be focused, successively, on the application of transition metal carbide catalysts in the transformation of first-generation (oils) and second-generation (lignocellulose) biomass to biofuels and fine chemicals.

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Tungsten carbides as selective deoxygenation catalysts: experimental and computational studies of converting C3 oxygenates to propene

Cited by 73 publications

References 43 publications

Fischer–Tropsch synthesis over early transition metal carbides and nitrides: CO activation and chain growth

Fischer–Tropsch synthesis over early transition metal carbides and nitrides: CO activation and chain growth

Bifunctional Catalysts for Upgrading of Biomass-Derived Oxygenates: A Review

Metal Carbides for Biomass Valorization

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