Characterization of Alumina, Silica, and Titania Supported Cobalt Catalysts

Voß, M.; Borgmann, D.; Wedler, G.

doi:10.1006/jcat.2002.3739

Cited by 181 publications

(51 citation statements)

References 31 publications

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“…It is known that the reducibility of cobalt oxide is strongly dependent on the support, loading and preparation conditions. 35,36 The reduction profiles of the cobalt samples are illustrated in Figure 4. According to the literature, 37 unsupported Co 3 O 4 contains one or two peaks close to each other in the temperature range of 200-400 ℃.…”

Section: Tprmentioning

confidence: 99%

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

et al. 2011

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Liquid phase hydrogenolysis of ethyl lactate to 1,2-propanediol was performed over silica supporting cobalt catalysts prepared by two different methods: precipitation-gel (PG) technique and deposition-precipitation (DP) procedure. The cobalt species (Co 3 O 4 /cobalt phyllosilicate) present in the corresponding calcined PG and DP catalysts were different as a consequence of the preparation methods, and Co-OH-Co olation and Si-O-Co oxolation molecular mechanisms were employed to elucidate the chemical phenomena during the different preparation procedures. In addition, the texture (BET), reduction behavior (TPR and in-situ XRD), surface dispersion and state of cobalt species (XPS), and catalytic performance differ greatly between the samples. Because of small particle size, high dispersion of cobalt species and facile reducibility, the Co/SiO 2 catalyst prepared by precipitation-gel method presented a much higher activity than the catalyst prepared by deposition-precipitation method. Metallic cobalt is assumed to be the catalytically active site for the hydrogenolysis reaction according to the catalytic results of both cobalt samples reduced at different temperatures and the structure changes after reaction.

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Section: Tprmentioning

confidence: 99%

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

et al. 2011

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“…The thermodynamically stable form of cobalt oxide under ambient temperature and pressure conditions is the Co 3 O 4 spinel phase [9,23]. Therefore, initially we investigated how pre-oxidized cobalt surfaces respond to different reactant mixing ratios (MRs).…”

Section: The Dynamic Transformation Of Cobalt Upon Changes In the Reamentioning

confidence: 99%

“…Perhaps the major application of cobalt-based catalysts is in the Fischer-Tropsch synthesis, since cobalt has been shown to efficiently convert syn gas (CO+H 2 ) to methane or liquid fuels [8,9,10,11]. Other applications of cobalt catalysts include partial oxidation reactions [12] and decomposition of methane to form hydrogen and carbon nanotubes or filamentous carbon [13,14].…”

Section: Introductionmentioning

confidence: 99%

Methanol oxidation over model cobalt catalysts: Influence of the cobalt oxidation state on the reactivity

Zafeiratos

Dintzer

Teschner

et al. 2010

Journal of Catalysis

116

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X-ray photoelectron and absorption spectroscopies (XPS and XAS) combined with on-line mass spectrometry were applied under working catalytic conditions to investigate the methanol oxidation on cobalt. Two cobalt oxidation states (Co3O4 and CoO) were prepared and investigated as regards their influence on the catalytic activity and selectivity. In addition adsorbed species were monitored in the transition of the catalyst from the non-active to the active state. It was unequivocally shown that the surface oxidation state of cobalt is readily adapted to the oxygen chemical potential in the CH3OH/O2 reaction mixture. In particular, even in rich to oxygen mixtures the Co3O4 surface is partially reduced, while the degree of surface reduction is higher as the methanol concentration in the mixture increases. The reaction selectivity depends on the cobalt oxidation state with the more reduced samples favouring the partial oxidation of methanol to formaldehyde. In the absence of oxygen, methanol is effectively reducing cobalt to the metallic state, promoting also hydrogen and CO production. Direct evidence of methoxy and formate species adsorbed on the surface upon reaction was found by analysing the O 1s and C 1s photoelectron spectra. However, the surface coverage of those species was not proportional to the catalytic activity, indicating that in the absence of surface oxygen, these species might act also as reaction inhibitors.

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“…The small first peak occurred at a temperature of about 225 • C and attributed to the reduction of trivalent Co oxide (Co 2 O 3 /Co 3 O 4 ) to divalent Co oxide (CoO). Voß et al [18] reported a similar temperature for the reduction of pure species Co 3 O 4 . They also proved the formation of such species on a supported system by XRD analysis.…”

Section: Metal Reduction and Dispersionmentioning

confidence: 80%

Influence of noble metals (Rh, Pd, Pt) on Co-saponite catalysts for HDS and HC of heavy oil

Hossain

2006

Chemical Engineering Journal

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Characterization of Alumina, Silica, and Titania Supported Cobalt Catalysts

Cited by 181 publications

References 31 publications

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

Methanol oxidation over model cobalt catalysts: Influence of the cobalt oxidation state on the reactivity

Influence of noble metals (Rh, Pd, Pt) on Co-saponite catalysts for HDS and HC of heavy oil

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