Hydrogen purification over lanthanum-doped iron oxides by WGSR

[Display omitted] •La decreases the particles size of hematite and magnetite.•La favors hematite reduction to produce magnetite.•La increases the activity of iron oxide-based catalysts in WGSR. Hydrogen technology has been greatly increased in last decades as a promising solution to protect the envi...

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Bibliographic Details
Published in:	Catalysis today Vol. 296; pp. 262 - 271
Main Authors:	Rangel, Maria do Carmo, Querino, Peterson Santos, Borges, Sarah Maria Santana, Marchetti, Sergio Gustavo, Assaf, José Mansur, Vásquez, Doris Polett Ruiz, Rodella, Cristiane Barbieri, Silva, Tatiana de Freitas, da Silva, Alisson Henrique Marques, Ramon, Adriana Paula
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 01-11-2017
Subjects:	Carbon monoxide Hematite Hydrogen Lanthanum Magnetite Wgsr Hematite Magnetite Lanthanum Carbon monoxide Hydrogen Wgsr
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Summary:	[Display omitted] •La decreases the particles size of hematite and magnetite.•La favors hematite reduction to produce magnetite.•La increases the activity of iron oxide-based catalysts in WGSR. Hydrogen technology has been greatly increased in last decades as a promising solution to protect the environment. When carbon-based feedstocks are used, such as natural gas, biomass and biogas, the water gas shift reaction (WGSR) plays an important step in the production of high pure hydrogen for several purposes. By this reaction, the residual carbon monoxide in the gaseous stream (coming from steam reforming of carbon-based feedstocks) can be converted to carbon dioxide and then removed from the stream, avoiding the poisoning of industrial metallic catalysts as well as of electrocatalysts in fuel cells. Aiming to obtain no toxic catalysts that can replace the commercial chromium-doped hematite catalysts, lanthanum-doped hematite was studied in this work. Iron oxide-based samples with different amounts of lanthanum (La/Fe (molar)=0.02; 0.08 and 0.2) were obtained by sol-gel method and calcined at 600°C. The catalysts were characterized by X-ray diffraction, specific surface area measurements, temperature programmed reduction, Raman spectroscopy, Mössbauer spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. It was found that lanthanum affected the textural and reducing properties of hematite, depending on the amount. Moreover, lanthanum oxide increased the activity of hematite by decreasing the size of hematite crystals and then increasing the number of exposed active sites. In addition, lanthanum favored hematite reduction to produce magnetite (active phase). The activity increased with the amount of lanthanum in solids, the lanthanum-richest sample being the most active catalyst.
ISSN:	0920-5861 1873-4308
DOI:	10.1016/j.cattod.2017.05.058