Influence of the method of preparation on the porous structure of perovskite oxides

Wachowski, L.

doi:10.1016/0257-8972(86)90003-4

Cited by 24 publications

(15 citation statements)

References 13 publications

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“…According to these findings, the principal goal, leading to great enhancement of catalytic properties, is the improvement of the textural properties of LaMnO 3 perovskites, increasing the exposed specific surface, enhancing the surface and bulk oxygen mobility, and increasing the average oxidation state of Mn (a higher proportion of Mn 4+ with respect to Mn 3+ ). Many efforts have been made to this end, resulting in the development of more efficient synthesis routes, such as co-precipitation [21,22], complexation [17,23], freeze/spray drying [22,[24][25][26], and sol-gel [27], as well as explosion processes [28,29] and high-energy ball milling [30,31]. Recently, sol-gel synthesis has emerged as an attractive technique for the production of high-purity and crystalline oxide powders at a significantly lower temperature than the conventional synthesis method [32,33].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

et al. 2019

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LaMnO3 (LM) catalysts with a molar ratio of citric acid (CA) to metal (La3+ + Mn2+) nitrates ranging from 0.5 to 2 (LM0.5 to LM2) were synthesized by the citrate sol–gel method with the aim of studying the effect of the citric acid ratio on the physicochemical properties and the catalytic performance in hydrocarbon oxidation. Structural and morphological properties of these catalysts were characterized by X-ray diffraction (XRD) and specific surface area (N2 adsorption) measurements, while the chemical composition was determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In the selected samples, additional characterizations were carried out by thermogravimetric and differential thermal analysis (TGA/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), temperature-programmed reduction by hydrogen (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the amount of citric acid used significantly influenced the TGA/DTA profile of gels along with the physicochemical properties of the catalysts. The XRD patterns are consistent with the perovskite formation as the main phase. The segregation of a small amount of Mn3O4, detected for molar ratios ranging between 0.5 and 1.5, suggested the formation of a slightly nonstoichiometric LaMn1−xO3 phase with a relatively high content of Mn4+. The catalytic performance was evaluated in the total oxidation of two selected hydrocarbons, toluene and propene, which represent typical volatile organic compounds (VOCs). Typically, three consecutive catalytic cycles were performed in order to reach steady-state performance in toluene and propene oxidation. Moreover, the stability of the catalysts under reaction conditions was investigated through 24-h experiments at 17% of toluene conversion. The catalysts LM1.2, LM1.3, and LM1.5 showed the best catalytic performance in both hydrocarbon oxidations, well comparing with the Pd/Al2O3 used as a reference.

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Section: Introductionmentioning

confidence: 99%

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

et al. 2019

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“…A ferroelectric so mode has been observed by means of Raman spectroscopy, 19 and SrHfO 3 also has interesting optical properties. 19,20 Various processing routes have been developed for the synthesis and characterisation of different perovskite-type NPs, such as coprecipitation, 20,21 the citrate process, 22 sol-gel chemistry, 23 solid state methods, 24 hydrothermal synthesis 25 and solvothermal processing. 26 However, there has been very little work on the synthesis of SrHfO 3 NPs, partly because of the high temperature required.…”

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High dielectric constant and capacitance in ultrasmall (2.5 nm) SrHfO₃ perovskite nanoparticles produced in a low temperature non-aqueous sol–gel route

et al. 2016

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“…However, the high calcination temperature of the prepared catalysts inevitably leads to large crystallite size and lower specific surface area (less than 5 m 2 /g) of the catalysts, limiting the potential applications of these materials. Therefore, it is urgent for us to develop a new method to prepare the kind of catalytic materials with large specific surface area [8,9]. In some catalytic oxidation, perovskite Co-based mixed oxides show excellent performance.…”

Section: Introductionmentioning

confidence: 99%

Effect of stoichiometric ratio of organic fuel to oxidizer on performance of La0.8Sr0.2CoO3 catalysts for CH4 combustion

Liu

2009

React Kinet Catal Lett

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Perovskite-type La 0.8 Sr 0.2 CoO 3 mixed oxides were prepared by D,L-alanine solution combustion synthesis and used successfully in CH 4 combustion as catalysts. These samples were characterized by means of XRD, FTIR, BET, and H 2 -TPR methods. The effects of stoichiometric ratio (u) of organic fuel to oxidizer on the structure and catalytic activities of the catalysts were studied.The results indicate that all La 0.8 Sr 0.2 CoO 3 mixed oxides with different u have perovskite structures. Their structures and catalytic activities vary along with the change of u. The catalytic activity of La 0.8 Sr 0.2 CoO 3 mixed oxide with u = 1.52 is the best among all the samples, whose T 50 and T 100 (the temperatures of methane conversions reaching 50 and 100%, respectively) are respectively 470°C and 550°C, which can be explained in terms of the smaller of average crystal size, higher specific surface area, bigger lattice distortion, lower activation energy, and higher mobility of chemically adsorbed oxygen on the surface and vacancy of the catalysts.

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Influence of the method of preparation on the porous structure of perovskite oxides

Cited by 24 publications

References 13 publications

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

High dielectric constant and capacitance in ultrasmall (2.5 nm) SrHfO₃ perovskite nanoparticles produced in a low temperature non-aqueous sol–gel route

Effect of stoichiometric ratio of organic fuel to oxidizer on performance of La0.8Sr0.2CoO3 catalysts for CH4 combustion

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Influence of the method of preparation on the porous structure of perovskite oxides

Cited by 24 publications

References 13 publications

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

The Effect of Citric Acid Concentration on the Properties of LaMnO3 as a Catalyst for Hydrocarbon Oxidation

High dielectric constant and capacitance in ultrasmall (2.5 nm) SrHfO3 perovskite nanoparticles produced in a low temperature non-aqueous sol–gel route

Effect of stoichiometric ratio of organic fuel to oxidizer on performance of La0.8Sr0.2CoO3 catalysts for CH4 combustion

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High dielectric constant and capacitance in ultrasmall (2.5 nm) SrHfO₃ perovskite nanoparticles produced in a low temperature non-aqueous sol–gel route