Thermodynamic and mechanism study of syngas production via integration of nitrous oxide decomposition and methane partial oxidation in the presence of 10%NiO–La0.3Sr0.7Co0.7Fe0.3O3−δ

Khajonvittayakul, Chalempol; Tongnan, Vut; Kangsadan, Tawiwan; Laosiripojana, Navadol; Jindasuwan, Sunisa; Hartley, Unalome Wetwatana

doi:10.1007/s11144-019-01600-1

Cited by 9 publications

(4 citation statements)

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“…In the 300-550 • C temperature range, a minor methane consumption is detected in the Ni containing catalyst. This process is accompanied by the production of water, carbon monoxide, carbon dioxide, and hydrogen, indicating some methane decomposition on Ni active sites, and methane combustion with adsorbed surface oxygen, following Equation ( 6) (Khajonvittayakul et al, 2019). Methane combustion was not detected on the bare pyrochlore indicating the lack of easily accessible surface oxygen.…”

Section: Ch 4 -Temperature-programmed Surface Reactionmentioning

confidence: 99%

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

2021

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Biogas is defined as the mixture of CH4 and CO2 produced by the anaerobic digestion of biomass. This particular mixture can be transformed in high valuable intermediates such as syngas through a process known as dry reforming (DRM). The reaction involved is highly endothermic, and catalysts capable to endure carbon deposition and metal particle sintering are required. Ni-pyrochlore catalysts have shown outstanding results in the DRM. However, most reported data deals with CH4/CO2 stoichiometric ratios resulting is a very narrow picture of the overall biogas upgrading via DRM. Therefore, this study explores the performance of an optimized Ni-doped pyrochlore, and Ni-impregnated pyrochlore catalysts in the dry reforming of methane, under different CH4/CO2 ratios, in order to simulate various representatives waste biomass feedstocks. Long-term stability tests showed that the ratio CH4/CO2 in the feed gas stream has an important influence in the catalysts' deactivation. Ni doped pyrochlore catalyst, presents less deactivation than the Ni-impregnated pyrochlore. However, biogas mixtures with a CH4 content higher than 60%, lead to a stronger deactivation in both Ni-catalysts. These results were in agreement with the thermogravimetric analysis (TGA) of the post reacted samples that showed a very limited carbon formation when using biogas mixtures with CH4 content <60%, but CH4/CO2 ratios higher than 1.25 lead to an evident carbon deposition. TGA analysis of the post reacted Ni impregnated pyrochlore, showed the highest amount of carbon deposited, even with lower stoichiometric CH4/CO2 ratios. The later result indicates that stabilization of Ni in the pyrochlore structure is vital, in order to enhance the coke resistance of this type of catalysts.

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Section: Ch 4 -Temperature-programmed Surface Reactionmentioning

confidence: 99%

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

2021

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“…As shown in Fig. 2, a large peak at 588 °C is observed with the H 2 consumption amount of 0.82 mmol g cat −1 on LSTF, which can be ascribed to the reduction of Fe and Ti in the B‐site, along with lattice oxygen release resulting in the formation of oxygen vacancies 7, 20. After thermal pretreatment at 800 °C in He atmosphere, lower hydrogen consumption amount of 0.15 mmol g cat −1 was shown over LSTF‐He, indicating that oxygen species was removed by He under high temperature.…”

Section: Resultsmentioning

confidence: 92%

“…For example, for the direct catalytic decomposition of N 2 O (Eq. ( 1)) over perovskite-type oxides, it has been reported that the catalytic performance is significantly influenced by the amount of active oxygen vacancies, and the desorption of produced oxygen from cat-alyst surface [5][6][7][8]. Hutchings and co-workers demonstrated the oxygen vacancies as active sites for direct decomposition of N 2 O with PrBaCoO 3 perovskite catalyst, and they indicated the mainly three steps of N 2 O decomposition on perovskite surface: (1) terminal oxygen of N 2 O first binds to an oxygen vacancy of the perovskite surface, and (2) the adsorbed N 2 O is subsequently decomposed to N 2 (g) and adsorbed oxygen (O*), and (3) the oxygen vacancy is regenerated via oxygen desorption [9].…”

Section: Introductionmentioning

confidence: 99%

Membrane Catalysis: N₂O Decomposition over La_0.2Sr_0.8Ti_0.2Fe_0.8O_3–δ Membrane with Oxygen Permeability

Liu

Cao

Liang

et al. 2021

Chemie Ingenieur Technik

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Dedicated to Prof. Dr. rer. nat. Ju ¨rgen Caro on the occasion of his 70th birthday Compared to conventional heterogeneous catalysis, membrane catalysis can facilitate in situ removal of inhibiting species on a catalyst, therefore effectively increases the reaction rate. Herein, kinetically controlled decomposition of N 2 O was studied employing a La 0.2 Sr 0.8 Ti 0.2 Fe 0.8 O 3-δ (LSTF) perovskite membrane, and the direct catalytic N 2 O decomposition over membrane surface was compared with membrane catalysis of N 2 O decomposition involving in situ oxygen removal. In the case of membrane catalysis, oxygen produced from N 2 O conversion can be in situ removed by using a LSTF oxygen-permeable membrane, thus increasing the amount of surface active sites for N 2 O decomposition. By sweeping hydrogen at one side of the membrane to consume the permeated oxygen from the other side N 2 O conversion was improved.

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“…Three distinct peaks at 325, 675, and 940 • C were found for NiO/CeO 2 -Cr 2 O 3 catalyst (c). The first two peaks were identical to the reduction of Ni 3+ to Ni 2+ and to the reduction of Ni 2+ to metallic nickel, respectively[34][35][36]. Some reduction of Cr 6+ ions to Cr 3+ ions could be combined in the first peak, whereas the second and the third peaks represented the reduction of the Cr 2 O 3 incorporated within the CeO 2 structure at the surface and bulk level, respectively.…”

mentioning

confidence: 85%

CO2 Hydrogenation to Synthetic Natural Gas over Ni, Fe and Co–Based CeO2–Cr2O3

et al. 2021

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CO2 methanation was studied over monometallic catalyst, i.e., Ni, Fe and Co; on CeO2-Cr2O3 support. The catalysts were prepared using one-pot hydrolysis of mixed metal nitrates and ammonium carbonate. Physicochemical properties of the pre- and post-exposure catalysts were characterized by X-Ray Powder Diffraction (XRD), Hydrogen Temperature Programmed Reduction (H2-TPR), and Field Emission Scanning Electron Microscope (FE-SEM). The screening of three dopants over CeO2-Cr2O3 for CO2 methanation was conducted in a milli-packed bed reactor. Ni-based catalyst was proven to be the most effective catalyst among all. Thus, a group of NiO/CeO2-Cr2O3 catalysts with Ni loading was investigated further. 40 % NiO/CeO2-Cr2O3 exhibited the highest CO2 conversion of 97.67% and CH4 selectivity of 100% at 290 °C. The catalytic stability of NiO/CeO2-Cr2O3 was tested towards the CO2 methanation reaction over 50 h of time-on-stream experiment, showing a good stability in term of catalytic activity.

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Thermodynamic and mechanism study of syngas production via integration of nitrous oxide decomposition and methane partial oxidation in the presence of 10%NiO–La0.3Sr0.7Co0.7Fe0.3O3−δ

Cited by 9 publications

References 50 publications

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

Membrane Catalysis: N₂O Decomposition over La_0.2Sr_0.8Ti_0.2Fe_0.8O_3–δ Membrane with Oxygen Permeability

CO2 Hydrogenation to Synthetic Natural Gas over Ni, Fe and Co–Based CeO2–Cr2O3

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Thermodynamic and mechanism study of syngas production via integration of nitrous oxide decomposition and methane partial oxidation in the presence of 10%NiO–La0.3Sr0.7Co0.7Fe0.3O3−δ

Cited by 9 publications

References 50 publications

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

Membrane Catalysis: N2O Decomposition over La0.2Sr0.8Ti0.2Fe0.8O3–δ Membrane with Oxygen Permeability

CO2 Hydrogenation to Synthetic Natural Gas over Ni, Fe and Co–Based CeO2–Cr2O3

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Membrane Catalysis: N₂O Decomposition over La_0.2Sr_0.8Ti_0.2Fe_0.8O_3–δ Membrane with Oxygen Permeability