In situ auto-gasification of coke deposits over a novel Ni-Ce/W-Zr catalyst by sequential generation of oxygen vacancies for remarkably stable syngas production via CO2-reforming of methane

Al‐Fatesh, Ahmed S.; Arafat, Yasir; Kasim, Samsudeen Olajide; Ibrahim, Ahmed A.; Abasaeed, Ahmed E.; Fakeeha, Anis H.

doi:10.1016/j.apcatb.2020.119445

Cited by 138 publications

(60 citation statements)

References 54 publications

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“…It is well established that the increase in the specific surface area is associated with the increase in catalytic activity. 31 , 32 The increase of the hydrogen consumption and the deactivation factor with the increase of the cerium loadings denotes that the promoter enhances the BET of the catalysts and the increase of carbon formation, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter

et al. 2021

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Yttria modified zirconia (YZ) supported on 5 wt % of Ni-based catalysts promoted with ceria (1−3 wt %) were prepared by the impregnation process to investigate their performance for dry reforming of methane. The reforming reactions, conducted at 700 °C and at atmospheric pressure using a CO 2 /CH 4 /N 2 fixed feed ratio of 3/3/1, with a total flow rate of 70 mL/ min, revealed that the ceria-promoted catalysts (xCe−Ni−YZ; x = 1−3 wt %) enhanced the CH 4 and CO 2 conversions as compared to the reference catalyst (Ni−YZ). A CO 2 conversion of 85% was exhibited by the 3Ce−Ni−YZ catalyst. Despite increased conversions, xCe−Ni−YZ catalysts showed more amounts of carbon deposition as evidenced by the values of TGA, and hence were found to be less stable as compared to the reference Ni−YZ catalyst. The used and fresh catalysts were characterized by BET, H 2 -TPR, XRD, TEM, Raman, TPD, and TGA. TEM images displayed nanoparticle sizes of Ni in the fresh catalysts, while carbon filaments were formed on the spent catalysts. The CO 2 -TPD, H 2 -TPR, and BET results revealed the existence of only weak and moderate basic sites, the increase of total hydrogen consumption, and the surface area values with the addition of the Ce promoter, respectively. The TGA analysis showed that the Ce promoter increased the carbon deposition, while the Raman results indicated the dominance of crystallinity due to the graphitized carbon.

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Section: Results and Discussionmentioning

confidence: 99%

Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter

et al. 2021

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“…The base sites strength of solid surface can provide electrons to the absorbed acid molecules (CO2) [51]. The irreversible adsorption of CO2 molecules was a better strategy to measure the number of alkali centers on the surface of solid base [52].…”

Section: Structural and Cobalt Oxidation States Of Co3o4-b-x Nanosheetsmentioning

confidence: 99%

Synergistic Lewis acid-base sites of ultrathin porous Co3O4 nanosheets with enhanced peroxidase-like activity

et al. 2021

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Surface Lewis acid-base sites in crystal structure may influence the physicochemical properties and the catalytic performances in nanozymes. Understanding the synergistic effect mechanism of Co 3 O 4 nanozymes towards substances (3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (H 2 O 2 )) induced by surface Lewis acid-base sites is important to enhance the efficiency for peroxidase-like reaction. Herein, ultrathin porous Co 3 O 4 nanosheets with abundant Lewis acid-base sites were prepared by sodium borohydride (NaBH 4 ) reduction treatment, which exhibited high-efficiency peroxidase-like activity compared with original Co 3 O 4 nanosheets. The Lewis acid-base sites for ultrathin porous Co 3 O 4 nanosheets nanozyme were owing to the coordination unsaturation of Co ions and the formation of defect structure. Ultrathin porous Co 3 O 4 nanosheets had 18.26-fold higher catalytic efficiency (1.27 × 10 −2 s −1 •mM −1 ) than that of original Co 3 O 4 (6.95 × 10 −4 s −1 •mM −1 ) in oxidizing TMB substrate. The synergistic effect of surface acid and base sites can enhance the interfacial electron transfer process of Co 3 O 4 nanosheets, which can be a favor of absorption substrates and the generation of reactive intermediates such as radicals. Furthermore, the limit of detection of hydroquinol was 0.58 μM for ultrathin porous Co 3 O 4 nanosheets, 965-fold lower than original Co 3 O 4 (560 μM). Besides, the linear range of ultrathin porous Co 3 O 4 nanosheets was widely with the concentration of 5.0-1,000 μM. Colorimetric detection of hydroquinol by agarose-based hydrogel membrane was provided based on excellent peroxidase-like properties. This study provided insights into designing high-performance nanozymes for peroxidase-like catalysis via a strategy of solid surface acid-base sites engineering.

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“…Owing to that, it has become necessary to consolidate Ni particles to make them less prone to deactivation in reforming reactions. Reduction of metal domain size to the minimum possible, the use of molecular layer deposition, Ni precursor in perovskites, and other different approaches have been explored towards achieving this [10][11][12][13]. Furthermore, the use of metal oxides as supports is another promising alternative that could supposedly improve the interaction between the active metal phase and the supports [12].…”

Section: Introductionmentioning

confidence: 99%

Dry Reforming of Methane with Ni Supported on Mechanically Mixed Yttria-Zirconia Support

et al. 2022

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This study focuses on CH4 reforming with CO2 over Ni supported on yttria mixed with zirconia support. Different loading of yttria was used to enhance the performance of Ni towards achieving the optimum activity. The physicochemical properties of both fresh calcined and used catalysts were studied using a range of characterization techniques. The specific surface area measurement by the BET method showed a progressive increase in the area with an increase in yttria loading. The monoclinic (m- ZrO2) and tetragonal (t- ZrO2) phases were identified on all the samples by the XRD analysis. A reduction in the intensity of m- ZrO2 was observed on adding Ni to the catalysts while the diffraction pattern of crystalline yttria was not identified. The reducibility analysis showed the influence of yttria. It induces the formation of NiYO3 species with stronger active metal-support interaction. From the catalytic test, 5Ni/10Y-Z-3215 had the highest feed conversion of about 68 and 88% for CH4 and CO2 respectively. The TEM analysis showed a uniform dispersion of NiO particles over the mixed yttria-zirconia support with no agglomeration of the active metal particles after the reaction. The measurement of the quantity of carbon deposits by the TGA revealed that the increase in yttria loading enhanced the gasification of carbon deposits with 5Ni/20Y-Z-3215 recording the lowest weight loss of about 28%. Graphical Abstract

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In situ auto-gasification of coke deposits over a novel Ni-Ce/W-Zr catalyst by sequential generation of oxygen vacancies for remarkably stable syngas production via CO2-reforming of methane

Cited by 138 publications

References 54 publications

Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter

Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter

Synergistic Lewis acid-base sites of ultrathin porous Co3O4 nanosheets with enhanced peroxidase-like activity

Dry Reforming of Methane with Ni Supported on Mechanically Mixed Yttria-Zirconia Support

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In situ auto-gasification of coke deposits over a novel Ni-Ce/W-Zr catalyst by sequential generation of oxygen vacancies for remarkably stable syngas production via CO2-reforming of methane

Cited by 138 publications

References 54 publications

Yttria Modified ZrO2Supported Ni Catalysts for CO2Reforming of Methane: The Role of Ce Promoter

Yttria Modified ZrO2Supported Ni Catalysts for CO2Reforming of Methane: The Role of Ce Promoter

Synergistic Lewis acid-base sites of ultrathin porous Co3O4 nanosheets with enhanced peroxidase-like activity

Dry Reforming of Methane with Ni Supported on Mechanically Mixed Yttria-Zirconia Support

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Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter

Yttria Modified ZrO₂Supported Ni Catalysts for CO₂Reforming of Methane: The Role of Ce Promoter