The mechanism of reduction of cobalt by hydrogen

Lin, Hsin; Chen, Yu Wen

doi:10.1016/j.matchemphys.2003.12.028

Cited by 178 publications

(55 citation statements)

References 19 publications

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“…In this work we argue that a reasonable explanation for the gas permeation redox effect was related to the silica pore connectivity around the metal oxide particle, which changed from Co 3 O 4 to CoO as reported in literature [19,[41][42][43]. The particles embedded in the porous silica matrix are schematically represented in Fig.…”

Section: Fig 1 the Volumetric Adsorption Systemsupporting

confidence: 67%

“…8, where several pores terminate at the particle surface. The redox effect confers structural changes in the lattice parameters of the particles from 0.8084nm (Co 3 O 4 ) to 0.426nm (CoO) [39][40][41][42][43][44]. However, cobalt oxide particles embedded in silica films using similar methods as in this work are very small to be detected by XRD (X-ray diffraction).…”

Section: Fig 1 the Volumetric Adsorption Systemmentioning

confidence: 68%

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Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ji¹,

Smart²,

Bhatia³

et al. 2015

Separation and Purification Technology

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This work investigated the permeation of binary gas mixtures in non-reducing (He/CO 2 ) and reducing (H 2 /Ar) conditions at temperatures ranging from 200 to 500 ºC. A common performance aspect under both non-reducing and reducing conditions was that the He and H 2 purity in the permeate stream was independent of temperature for the tested binary gas mixtures, except at very high He/CO 2 or H 2 /Ar concentrations (≥90/10) in the retentate stream. Under non-reducing conditions, the transport of gases was consistent with molecular sieving properties of silica derived membranes, and He permeance was constant irrespective of the He/CO 2 binary concentration tested.An anomalous H 2 transport was observed under reduced conditions, as unexpectedly the H 2 permeance was higher for gas mixtures instead of single gas. Further tests showed that H 2 permeance increased 170% as the gas mixture changed from single H 2 gas to H 2 /Ar gas mixtures.This was attributed to the experimental procedure, as the membranes were partially reduced each day and tested for gas permeation from pure H 2 to lower H 2 concentration in gas mixtures. Under these partial reducing conditions, H 2 slowly reacts with the surface of the dense Co 3 O 4 particle, thus 2 forming a porous CoO region. The increase in H 2 permeance was therefore attributed to improved pore connectivity between the silica structure and the porous CoO region.

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Section: Fig 1 the Volumetric Adsorption Systemsupporting

confidence: 67%

Section: Fig 1 the Volumetric Adsorption Systemmentioning

confidence: 68%

Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ji¹,

Smart²,

Bhatia³

et al. 2015

Separation and Purification Technology

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“…CoO ? Co [18,19] with an increase in the reduction temperatures, as the crystallite size increases [20,21]. In fact, for a Co 3 O 4 nano-sized (20-30 nm) investigated in our laboratory, two reduction steps have been clearly identified by two peaks, respectively at about 300°C and 400°C.…”

Section: Resultsmentioning

confidence: 71%

On the Catalytic Activity of Cobalt Oxide for the Steam Reforming of Ethanol

Tuti¹,

Pepe²

2007

Catal Lett

103

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The paper presents an investigation on the catalytic activity for the ethanol steam reforming of Co 3 O 4 oxidized, reduced and supported on MgO, and of CoO in MgO solid solution. Only samples containing metallic cobalt are found to be active for reforming reaction. H 2 -TPR characterization of aged samples shows that reaction mixture oxidizes a small fraction of metallic cobalt to Co +2 . A distinct role of Co +2 and Co 0 in the reaction is enlightened.

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“…The obtained TPR profiles are presented in Figure 8; these calcined samples showed four distinguished reduction peaks. The XRD results showed the presence of various oxidic phases of Co3O4, Fe2O3, Fe3O4, and Mn2O3 in the fresh catalyst ( Figure 3); the Co3O4 phase is reduced according to the following reactions and steps [31,32]: Co3O4 +H2 → 3CoO + H2O 3CoO + 3H2 → 3 Co° + 3H2O…”

Section: Effect Of Drying Timementioning

confidence: 99%

Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins

Abdouss

Arsalanfar

Mirzaei

et al. 2017

Bull. Chem. React. Eng. Catal.

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The MgO-supported Fe-Co-Mn catalysts, prepared using co-precipitation procedure, were tested for production of light olefins via CO hydrogenation reaction. The effect of a range of drying conditions including drying temperature and drying time on the structure and catalytic performance of Fe-Co-Mn/MgO catalyst for Fischer-Tropsch synthesis was investigated in a fixed bed micro-reactor under the same operational conditions of T = 350 °C, P = 1 bar, H2/CO = 2/1, and GHSV = 4500 h -1 . It was found that the catalyst dried at 120 °C for 16 h has shown the best catalytic performance for CO hydrogenation. Furthermore, the effect of drying conditions on different surface reaction rates was also investigated and it was found that the precursors drying conditions influenced the rates of different surface reactions. Characterization of catalyst precursors and calcined samples (fresh and used) was carried out using powder X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Brunauer-Emmett-Teller (BET) measurements, Temperature Programmed Reduction (TPR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). Characterization results showed that different investigated variables (drying conditions) influenced the structure, morphology and catalytic performance of the ternary catalysts.

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The mechanism of reduction of cobalt by hydrogen

Cited by 178 publications

References 19 publications

Improved pore connectivity by the reduction of cobalt oxide silica membranes

Improved pore connectivity by the reduction of cobalt oxide silica membranes

On the Catalytic Activity of Cobalt Oxide for the Steam Reforming of Ethanol

Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins

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