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Cu–Zn–Al hydrotalcites as precursors of catalysts for the production of hydrogen from methanol

The possibility of a wide use of hydrogen as fuel of proton exchange membrane fuel-cells forces to the development of selective catalytic materials for the oxidative steam reforming of methanol (OSRM) to produce H 2 essentially free from CO. Cu/ZnO/Al 2O 3 catalysts of OSRM process have been obtaine...

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Bibliographic Details
Published in:Solid state ionics 2005-12, Vol.176 (39), p.2917-2922
Main Authors: Costantino, U., Marmottini, F., Sisani, M., Montanari, T., Ramis, G., Busca, G., Turco, M., Bagnasco, G.
Format: Article
Language:English
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Summary:The possibility of a wide use of hydrogen as fuel of proton exchange membrane fuel-cells forces to the development of selective catalytic materials for the oxidative steam reforming of methanol (OSRM) to produce H 2 essentially free from CO. Cu/ZnO/Al 2O 3 catalysts of OSRM process have been obtained from hydrotalcite-like precursors with nominal formula Cu 1− x− y Zn y Al x (OH) 2(CO 3) x/2 ( x = 0.23–0.42, y = 0.31–0.58) and prepared by homogeneous precipitation from metal chlorides solutions in the presence of urea. The catalysts were obtained after thermal decomposition of the hydrotalcites at 450 °C, followed by in situ reduction with H 2. X-ray powder diffraction (XRPD) patterns of the precursors showed the presence of the hydrotalcite phase with minor amounts of a Zn-rich paratacamite phase (Cu 2− x Zn x (OH) 3Cl) whose amount increases with increasing Cu content. XRPD patterns of thermally treated samples show only the lines of CuO and ZnO phases; Al 2O 3 and/or aluminates may be present as amorphous phases. The BET surface areas of the samples are in the range 110–220 m 2 g − 1 and increase with increasing Al content. The catalytic activity in the OSRM process is appreciable from about 200–250 °C and methanol conversions up to 90–95% are obtained at temperatures of 300–400 °C. Hydrogen is the main product, and its yield reaches values up to 2.7 mol/mol of methanol. Carbon monoxide content is under the detection limit (500 ppm) of the detector.
ISSN:0167-2738
1872-7689
DOI:10.1016/j.ssi.2005.09.051