Advances in designing perovskite catalysts

Tanaka, Hiroyuki; Misono, Makoto

doi:10.1016/s1359-0286(01)00035-3

Cited by 440 publications

(232 citation statements)

References 19 publications

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“…Indeed, it was reported that catalytic activity of perovskites can be increased through the addition of small amounts of noble metals [19,27,28]. This is confirmed by the present data (Table 2 and Fig.5) for Co-based perovskites doped with either Pt or Pd.…”

Section: -Effect Of Noble Metals Additionsupporting

confidence: 91%

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Rossetti

Buchneva

Biffi

et al. 2009

Applied Catalysis B: Environmental

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ABO3 perovskite-like catalysts are known to be sensitive to sulphur-containing compounds. Possible solutions to increase resistance to sulphur are represented by either catalyst bed protection with basic guards or catalyst doping with different transition or noble metals. In the present work La(1-x)A'xCoO3, La(1-x)A'xMnO3 and La(1-x)A'xFeO3, with A' = Ce, Sr and x=0, 0.1, 0.2, either pure or doped with noble metals (0.5 wt% Pt or Pd), were prepared in nano-powder form by flame pyrolysis. All the catalysts were tested for the catalytic flameless combustion of methane, monitoring the activity by on-line mass spectrometry. The catalysts were then progressively deactivated in operando with a new procedure, consisting of repeated injection of some doses of tetrahydrothiophene (THT), usually employed as odorant in the natural gas grid, with continuous analysis of the transient response of the catalyst. The activity tests were then repeated on the poisoned catalyst. Different regenerative treatments were also tried, either in oxidising or reducing atmosphere.Among the unsubstituted samples, higher activity and better resistance to poisoning have been observed in general with manganites with respect to the corresponding formulations containing Co or Fe at the B-site. The worst catalyst showed LaFeO3, from both the points of view of activity and of resistance to sulphur * Corresponding author: fax +39-02-50314300, e-mail ilenia.rossetti@unimi.it 2 poisoning. La0,9Sr0,1MnO3 showed, the best results, exhibiting very high activity and good resistance even after the addition of up to 8.4 mg of THT per g of catalyst.Interesting results were attained also by adding Sr to Co-based perovskites. Sr showed a first action by forcing Mn or Co in their highest oxidation state, but, in addition, it could also act as a sulphur guard, likely forming stable sulphates due to its basicity. Among noble metals, Pt doping proved beneficial in improving the activity of both the fresh and the poisoned catalyst.Keywords: Methane, catalytic combustion; Sulphur poisoning; Perovskite-like catalysts. -INTRODUCTIONThe catalytic flameless combustion (CFC) of methane outperforms conventional flame combustion because of lower emission of pollutants (HC, CO and NOx) and high thermal efficiency. The catalysts traditionally used for CFC are mainly based on supported noble metals, such as Pd and Pt, which ensure high activity, however accompanied by some drawbacks, due to high cost and poor thermal and chemical stability. La-based catalysts with ABO3 perovskite-like structure [1][2][3][4] have been proposed as a valid alternative for the present application. Indeed, perovskite catalysts combine low cost, thermo-chemical stability at high operating temperature and satisfactory catalytic activity [5][6][7][8]. In spite of this, there are still some open questions, especially regarding their resistance to sulphur poisoning when used for the CFC of methane. Indeed, the poisoning mechanism of perovskite-like catalysts has not been completely understood a...

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Section: -Effect Of Noble Metals Additionsupporting

confidence: 91%

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Rossetti

Buchneva

Biffi

et al. 2009

Applied Catalysis B: Environmental

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“…2 These materials can be considered extremely important due to their electronic, optic and catalytic properties, among others. [1][2][3][4][5] In recent decades, many routes have been used for preparing mixed oxides with the perovskite structure such as the conventional ceramic powder technology, the Pechini process, the chelating precursor method, the proteic sol gel process and the combustion synthesis, among others. [5][6][7][8][9] In general, these methods aim at obtaining a material with high homogeneity, low amount of impurities, and phase, particle size and surface area suitable for different applications.…”

Section: Introductionmentioning

confidence: 99%

“…Nickel usually adopts a formal charge of Ni 2+ but can (in rare earth or alkaline earth ternary metal oxides) form 3+ ions. 2 These materials can be considered extremely important due to their electronic, optic and catalytic properties, among others. [1][2][3][4][5] In recent decades, many routes have been used for preparing mixed oxides with the perovskite structure such as the conventional ceramic powder technology, the Pechini process, the chelating precursor method, the proteic sol gel process and the combustion synthesis, among others.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of LaNiO3 perovskite by the modified proteic gel method and study of catalytic properties in the syngas production

Santos¹,

Souza²,

Ruiz³

et al. 2012

J. Braz. Chem. Soc.

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Este trabalho descreve um estudo sobre a síntese da perovsquita LaNiO 3 via método do gel proteico, variando quantidade de colágeno e sobre a atividade catalítica de LaNiO 3 e LaNiO 3 /Al 2 O 3 na produção de gás de síntese (CO + H 2 ). Os padrões de difração de raios X revelaram a formação da estrutura perovsquita em todas as amostras preparadas pelo método de síntese do gel protéico, variando a quantidade de colágeno e após calcinações a 700 ºC por 2 h. O catalisador LaNiO 3 /Al 2 O 3 preparado pelo método de impregnação mostrou picos de difração nos difratogramas atribuídos a LaNiO 3 e ao suporte (Al 2 O 3 ). Este catalisador apresentou: área superficial específica de 46,1 m 2 g -1 , dois picos de redução no perfil de redução à temperatura programada (RTP) e 46% de conversão do metano (através da oxidação parcial do metano utilizando oxigênio) depois de 18 h de reação.This work describes a study on the synthesis of LaNiO 3 perovskites via the modified proteic gel method, varying collagen content and on the catalytic activity of LaNiO 3 and LaNiO 3 /Al 2 O 3 in the syngas (CO + H 2 ) production. X-ray diffraction patterns revealed the formation of perovskite structure in all samples prepared by proteic gel synthesis method, varying collagen content and after calcinations at 700 ºC for 2 h. LaNiO 3 /Al 2 O 3 catalyst prepared by the impregnation method showed diffraction peaks due to the perovskite structure and to the support (Al 2 O 3 ). This catalyst presented: specific surface of 46.1 m 2 g -1 , two reduction peaks in the temperature programmed reduction (TPR) profile and 46% of methane conversion (by the partial oxidation of methane using oxygen) after 18 h of reaction.Keywords: LaNiO 3 perovskites, collagen, syngas production, partial oxidation of methane IntroductionPerovskite mixed oxides are ceramic materials that combine metal elements with non-metallic ones, usually with the general formula ABO 3 , where A represents a lanthanide or alkaline earth ion and B a trivalent ion of a transition metal. 1 LaNiO 3 perovskite oxides have been widely investigated among the rare earth perovskites containing Ni +3 . Nickel usually adopts a formal charge of Ni 2+ but can (in rare earth or alkaline earth ternary metal oxides) form 3+ ions. 2 These materials can be considered extremely important due to their electronic, optic and catalytic properties, among others. [1][2][3][4][5] In recent decades, many routes have been used for preparing mixed oxides with the perovskite structure such as the conventional ceramic powder technology, the Pechini process, the chelating precursor method, the proteic sol gel process and the combustion synthesis, among others. [5][6][7][8][9] In general, these methods aim at obtaining a material with high homogeneity, low amount of impurities, and phase, particle size and surface area suitable for different applications. [5][6][7][8] The effects of the routes of preparation and calcination Santos et al. 1859 Vol. 23, No. 10, 2012 temperature on the phase composition and crystalline st...

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“…A perovskita de formulação ABO 3 apresenta estrutura em que os cátions de maior raio iônico, como os metais alcalinos ou lantanídeos, ocupam os sítios A com número de coordenação 12 e os cátion menores, geralmente metais de transição d com número de coordenação 6, ocupam o sítio B [1]. Os óxidos com estrutura tipo perovskita têm sido objetos de interesse da comunidade de pesquisa devido às suas propriedades físicas e químicas.…”

Section: Introductionunclassified

Caracterização óptica e estrutural de ortoferritas de lantânio dopadas com cromo e alumínio

et al. 2018

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ResumoEsse trabalho teve como objetivo sintetizar óxidos com a estrutura tipo perovskita de composição LaFeO 3 , LaFe 0,8 Al 0,2 O 3 e LaFe 0,8 Cr 0,2 O 3 pelo método sol-gel proteico, visando sua aplicação como pigmento cerâmico. Os pós resultantes do processo de síntese foram calcinados a 600 e 800 °C e em seguida caracterizados por difração de raios X com refinamento Rietveld, microscopia eletrônica de varredura (MEV), microscopia eletrônica de transmissão (MET), espectroscopia na região do UV-visível e colorimetria CIE-L*a*b*. De acordo com os difratogramas de raios X, todos os pós calcinados foram monofásicos com estrutura tipo perovskita ortorrômbica. As imagens de MEV e MET revelaram que os pós foram porosos e nanométricos. As ferritas de lantânio sem dopagem apresentaram cores em tons pastel, sendo mais claros nos pós dopados com alumínio. Já a ferrita dopada com cromo apresentou coloração marrom claro. As colorações foram mais intensas com o aumento da temperatura de calcinação. Palavras-chave: pigmento, gelatina, perovskita, ferrita. Abstract

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Advances in designing perovskite catalysts

Cited by 440 publications

References 19 publications

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

Synthesis of LaNiO3 perovskite by the modified proteic gel method and study of catalytic properties in the syngas production

Caracterização óptica e estrutural de ortoferritas de lantânio dopadas com cromo e alumínio

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