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

Abstract

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...

Nickel-based perovskite catalysts: synthesis and catalytic tests in the production of syngas

“…It is possible to observe that even at 900 ºC, the sample still show a mass loss, which can be attributed to the decomposition of carbonates formed [17]. It was possible to observe a slight mass gain above 670 and 830 °C in the samples LN-3 and L7S3N-3, respectively, due to the oxidation reactions, as observed in other studies for perovskite of nickel-based synthesis [16,17]. Fig.…”

“…The method is distinguished by its simplicity and ability to obtain crystalline materials with high purity and good stoichiometric control. It is an alternative route to obtain oxides with high efficiency and low cost [16]. Researchers showed that it is possible to obtain perovskites through the collagen-modified proteic gel method with formation of a single-phase material at 700 ºC [6,16].…”

“…It is an alternative route to obtain oxides with high efficiency and low cost [16]. Researchers showed that it is possible to obtain perovskites through the collagen-modified proteic gel method with formation of a single-phase material at 700 ºC [6,16]. In this work, oxides of La 1-x Sr x NiO 3 (x= 0.0, 0.3 or 0.7) type were synthesized using the modified proteic gel method using collagen as an organic precursor.…”

Mechanochemically assisted synthesis and visible light photocatalytic properties of lanthanum nickel oxide nanoparticles

“…For example, LaNiO3 is a promising candidate as an electrode constituent material due to excellent electrical properties [1][2][3]. Additionally, LaNiO3 and its derived materials have been used as catalysts because they show high catalytic activity in several chemical reactions, such as the evolution of hydrogen gas from organic compounds [4][5][6][7][8]. Particularly, the visible-light-driven photocatalytic activity of LaNiO3 has lately received particular attention in the degradation of organic compounds [9][10][11] and hydrogen production [12,13].…”

“…LaNiO3 has been synthesized using various techniques, such as sol-gel [5,10,12,13], combustion [1,6,8,9,[14][15][16][17], hydrothermal [7,18], microwave heating [19], spray pyrolysis [4], reverse microemulsion [11], polymerization [20], and molten salt [21].…”