The consequences of surface heterogeneity of cobalt nanoparticles on the kinetics of CO methanation

Castillo, José; Arteaga-Pérez, Luis E.; Karelovic, Alejandro; Jiménez, Romel

doi:10.1039/c9cy01753d

Cited by 7 publications

(4 citation statements)

References 56 publications

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“…32,33 Recently, enhanced catalytic activity was reported for cobalt nanoparticles associated with high surface heterogeneity in terms of size and distribution. 34 The electrocatalytic activity for OER is usually measured based on the overpotential required to reach a current density of 10 mA/cm 2 with respect to the standard reaction potential of OER (1.23 V with respect to (wrt) RHE). 35,36 In our studies, the overpotential required to reach the current density is found to be 350 mV.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The differences in catalytic activities may be attributed to the dense and uniform deposition in the case of CoNPs prepared in the neat maline medium unlike that of CoNP AqMal /GS, as shown in Figure . The distinct morphology and scattered distribution of the relatively thin CoNP AqMal clusters (vs CoNP Mal ) favor the exposure of a large number of catalytically active edges, which contributes toward superior catalytic activity. , Recently, enhanced catalytic activity was reported for cobalt nanoparticles associated with high surface heterogeneity in terms of size and distribution …”

Section: Results and Discussionmentioning

confidence: 99%

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Single-Step Electrochemical Synthesis of Cobalt Nanoclusters Embedded on Dense Graphite Sheets for Electrocatalysis of the Oxygen Evolution Reaction

Renjith

Lakshminarayanan

2020

ACS Appl. Nano Mater.

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Thin nanoparticle clusters have been proven to be excellent electrocatalysts as the number of active centers present in these films is several folds higher than their thicker counterparts. However, reports to date suggest that it is highly challenging to fabricate such nanoparticle-modified electrodes and usually involves multistep routes of chemical synthesis, purification, and finally, embedment onto the electrode surface, often at very high temperature. To the best of our knowledge, this is the first time that a single-step electrochemical preparation and in situ deposition of thin clusters of cobalt nanoparticle onto the electrode surface are being reported. The thickness of the nanoparticle clusters was not uniform and varied between 20 and 90 nm. The cobalt nanoparticles on the dense graphite sheet reported could attain an oxygen evolution reaction (OER) current of 10 mA/cm 2 at a very low overpotential of 350 mV despite a very low catalyst loading. The turnover frequency (0.78 s −1 ) and activation energies (21 kJ/mol) for OER indicate that these are potential anode catalysts in the alkaline media-based oxygen evolution reaction. The fabrication methodology of these ready-to-use cobalt-based graphite substrates has several advantages like the use of an environment-friendly medium such as an aqueous deep eutectic solvent mixture, inexpensive graphite sheet, and rapid single-step preparation under ambient room-temperature conditions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Single-Step Electrochemical Synthesis of Cobalt Nanoclusters Embedded on Dense Graphite Sheets for Electrocatalysis of the Oxygen Evolution Reaction

Renjith

Lakshminarayanan

2020

ACS Appl. Nano Mater.

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“…3), which should in principle arise from the catalytic decomposition of carboxylic anhydrides [37], with the concomitant formation of methane. The formation of methane in this temperature range should be associated to the CO methanation activity of the cobalt phase, which also produces water [38,39]. From ICP analyses.…”

Section: Cobalt Particle Size Confinement Crystallographic Phase and Compositionmentioning

confidence: 98%

Beyond confinement effects in Fischer-Tropsch Co/CNT catalysts

Ghogia

Machado

Cayez

et al. 2021

Journal of Catalysis

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Fischer-Tropsch catalyst preparation parameters, such as cobalt precursor and impregnation solvent, determine structure and in fine catalytic performances of Co-based catalysts. Co particles of 3-7 nm mean size were prepared by incipient wetness impregnation on surface-oxidized CNT. In this work the crucial impact of the chemistry operating between the Co precursor and the support during catalyst preparation on the catalyst properties is demonstrated and the influence of CNT surface chemistry on catalyst characteristics has been assessed. Very good correlations were found between: i) the reduction degree of the catalysts and the concentration of the Co(OOC-) surface species; ii) the Co hcp /Co fcc ratio and the amount of CO-releasing groups on the support surface; iii) the extent of hydrogen spillover and the concentration of quinone surface groups. The initial catalytic activity could only be correlated to a combination of catalyst features: percentage of Co hcp , Co confinement, hydrogen spillover, and surprisingly the inverse of the Co initial particle size. No significant differences in S C5+ selectivity were observed, in accordance with comparable final Co particle size. Finally, the stability of the catalyst can be correlated with the initial Co particle size and the percentage of Co hcp in the catalyst. These results confirm the significant impact of the precursor/support couple on the structure and performance of Co/CNT catalysts, and reveal for the first time an inverse correlation between Co particle size and activity, which is attributed to the confined Co hcp phase.

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“…The fact that the co-precipitated Co 0.1 Ce 0.9 O x catalysts have higher apparent activation energies than the impregnated Co/CeO 2 catalysts seems to be related to the H 2 -TPR results that the co-precipitation method can provide a stronger interaction between cobalt oxides and ceria than the wet impregnation method. Castillo et al [64] reported that the CO consumption turnover rate was significantly lower for smaller cobalt nanoparticles during CO methanation over Co/SiO 2 catalysts with different cobalt particle sizes ranging from 4 to 33 nm. The apparent activation energy was lower for smaller cobalt nanoparticles.…”

Section: Co2 Methanationmentioning

confidence: 99%

CO and CO2 Methanation over CeO2-Supported Cobalt Catalysts

2022

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CO2 methanation is a promising reaction for utilizing CO2 using hydrogen generated by renewable energy. In this study, CO and CO2 methanation were examined over ceria-supported cobalt catalysts with low cobalt contents. The catalysts were prepared using a wet impregnation and co-precipitation method and pretreated at different temperatures. These preparation variables affected the catalytic performance as well as the physicochemical properties. These properties were characterized using various techniques including N2 physisorption, X-ray diffraction, H2 chemisorption, temperature-programmed reduction with H2, and temperature-programmed desorption after CO2 chemisorption. Among the prepared catalysts, the ceria-supported cobalt catalyst that was prepared using a wet impregnation method calcined in air at 500 °C, and reduced in H2 at 500 °C, showed the best catalytic performance. It is closely related to the large catalytically active surface area, large surface area, and large number of basic sites. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study revealed the presence of carbonate, bicarbonate, formate, and CO on metallic cobalt.

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The consequences of surface heterogeneity of cobalt nanoparticles on the kinetics of CO methanation

Abstract: The CO hydrogenation reaction was studied under methanation conditions (H2/CO >3, 250–300 °C) on Co/SiO2 catalysts with different mean Co nanoparticle size (dp = 4 nm, 13 nm and 33 nm).

Cited by 7 publications

References 56 publications

Single-Step Electrochemical Synthesis of Cobalt Nanoclusters Embedded on Dense Graphite Sheets for Electrocatalysis of the Oxygen Evolution Reaction

Single-Step Electrochemical Synthesis of Cobalt Nanoclusters Embedded on Dense Graphite Sheets for Electrocatalysis of the Oxygen Evolution Reaction

Beyond confinement effects in Fischer-Tropsch Co/CNT catalysts

CO and CO2 Methanation over CeO2-Supported Cobalt Catalysts

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