The Effect of La2O3 on Ni/Al2O3 Catalyst for Methanation at Very Low COx/H2 Ratio

Michalska, Kamila; Kowalik, Paweł; Próchniak, Wiesław; Borowiecki, T.

doi:10.1007/s10562-018-2302-y

Cited by 8 publications

(5 citation statements)

References 28 publications

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“…The selectivity of catalysts is slightly changed after introduction of cerium. The observed changes of the activity of promoted catalysts are consistent with recently published data[32][33][34][35][36]. An increased activity of Ce and La promoted nickel catalysts has been often attributed…”

supporting

confidence: 91%

“…Such discrepancy may result from limited accessibility of surface sites and partial coverage of nickel crystallites by the support. in the literature to the improved nickel dispersion and changes of the acid-base properties of catalysts [32][33][34][35][36]. Figure 3 shows the results of durability studies of catalysts in CO 2 methantion reaction performed at 475 °C.…”

Section: Properties Of Catalysts Determined Prior To the Co 2 Methanamentioning

confidence: 99%

“…Nickel dispersion has been also improved by the use of suitable promoters and modifiers, e.g. Ce [29][30][31][32], La [33][34][35][36][37], Mo [38], W [39], Mn [40], Fe [41][42][43]. Hydrogen sulfide (H 2 S) is found to be the most unfavorable component of biogas.…”

Section: Introductionmentioning

confidence: 99%

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CO2 Methanation in the Presence of Ce-Promoted Alumina Supported Nickel Catalysts: H2S Deactivation Studies

et al. 2019

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The performance of alumina supported unpromoted and cerium promoted nickel catalysts in CO 2 methanation reaction was investigated. It was found that the activity of catalysts in CO 2 methanation reaction at low reaction temperatures can be improved by the increase in nickel loading and introduction of cerium promoter. The catalysts showed high resistance for sintering and coking at high reaction temperatures. A few stages of catalysts deactivation by H 2 S in the methanation reaction carried out at 475 °C with the time on stream were identified. It was found that an introduction of H 2 S to the stream (8 ppm) did not induce rapid decrease of activity. Slight and then strong drop of CO 2 conversion and simultaneously the loss of methane selectivity was observed after specific time, depending on the catalysts composition. Deactivation of catalysts was related to the nickel content and the presence of cerium. X-ray diffraction studies indicated small changes of crystallite size with the time on stream. Raman spectroscopy studies pointed out that deactivation of catalysts was not connected with formation of carbon deposits. An in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy studies showed that exposition of catalysts to the reaction mixture containing the traces of H 2 S led to the blocking of nickel active sites responsible for CO 2 and H 2 activation and successive transformation to carbonyl and formate species.

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supporting

confidence: 91%

Section: Properties Of Catalysts Determined Prior To the Co 2 Methanamentioning

confidence: 99%

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CO2 Methanation in the Presence of Ce-Promoted Alumina Supported Nickel Catalysts: H2S Deactivation Studies

et al. 2019

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“…The close contact between the Ni and La phases results in the formation of La 2 O 2 CO 3 intermediates, which inhibits carbon deposition and enhances the gasification of carbon by hydrocarbons (CH x and carbon atoms) on the surface of Ni [114]. The strong interaction between the Ni and La phases results in less sintering of the metal [115]. The improved resistance to coking and sintering with La leads to enhanced catalyst stability, which is sustainable.…”

Section: Stability Performance Of La Addition In Ni-based Catalysts F...mentioning

confidence: 99%

Performance of Ni-Based Catalysts with La Promoter for the Reforming of Methane in Gasification Process

Chen,

Wang

2024

Catalysts

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The deactivation of active sites caused by high-temperature sintering and the deposition of a large amount of carbon are the main difficulties in the reforming of methane using Ni-based catalysts. La, as a promoter, has an ameliorating effect on the defects of Ni-based catalysts. In this article, the mechanism of action of Ni-based catalysts with the introduction of the rare-earth metal additive La was reviewed, and the effects of La on the methane-reforming performance of Ni-based catalysts were examined. The physical properties, alkalinity, and activity of Ni-based catalysts can be enhanced by the use of the auxiliary agent La, which promotes the conversion of CH4 and CO2 as well as the selectivity towards H2 and CO formation in the reforming of methane. The reason why the Ni-based catalysts could maintain long-term stability in the presence of La was discussed. Furthermore, the current state of research on the introduction of different amounts of La in the reforming of methane at home and abroad was analyzed. It was found that 2–5 wt.% La is the most optimal quantity for improving the catalyst activity and stability, as well as the CO2 chemisorption. The limitations and directions for future research in the reforming of methane were discussed.

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“…Apart from the thermal stability, other benefits of La doping are also evident. These include catalytic activity and/or selectivity, ,− dispersibility of active secondary phases onto the alumina surface, ,, improvements to mechanical, ,, , , redox, and acid–base properties, , as well as resistance to coke deposition . Addition of lanthanum also limits the grain size in sintered alumina samples (e.g., after sintering at 1800 °C for 4 h). , On the other hand, in unsintered samples (after calcination at 450 °C) Schaper et al observed a decline in surface area with increasing La content (from 200 to 161 m 2 /g for 0 to 5 mol % La, respectively) …”

Section: Temperature Stabilization Of Aluminasmentioning

confidence: 99%

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

Heveling

2023

Ind. Eng. Chem. Res.

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Advanced materials based on lanthanum–aluminum oxides are useful for many practical applications, not the least in catalysis, energy conversion and energy storage systems designed for a sustainable world economy. The three main La–Al–O (LAO) combinations of commercial interest are La-doped aluminas (LDA), lanthanum monoaluminate (LMA, a perovskite), and lanthanum hexaaluminate (LHA). Usually, the literature treats doped aluminas, perovskites, and hexaaluminates separately. The current review tries to identify common trends and features with respect to structure, synthesis, and applications of LAOs, which should lead to a more holistic understanding of their chemistry. This, in turn, should trigger innovative ideas with respect to new or improved applications. Apart from a variety of uses at low temperatures, the main advantages of LDA, LMA, LHA, and related compounds are their high-temperature stability and the extended applicability that comes with it.

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The Effect of La2O3 on Ni/Al2O3 Catalyst for Methanation at Very Low COx/H2 Ratio

Cited by 8 publications

References 28 publications

CO2 Methanation in the Presence of Ce-Promoted Alumina Supported Nickel Catalysts: H2S Deactivation Studies

CO2 Methanation in the Presence of Ce-Promoted Alumina Supported Nickel Catalysts: H2S Deactivation Studies

Performance of Ni-Based Catalysts with La Promoter for the Reforming of Methane in Gasification Process

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

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