title: Methanol conversion over a Pd5Cu/Al2O3-CeO2 catalyst: an FT-IR study and reaction mechanism.
abstract: A catalyst composed of a Pd(5)Cu mixed oxide supported over Al(2)O(3)-CeO(2) with general formula Pd(5)CuO(x)/Al(2)O(3)-CeO(2) (Al/Ce atomic ratio=1/1) has been prepared by a wet impregnation method and tested in the methanol conversion. The structural and morphological characterization of the catalyst evidences that it is a mesoporous material thermally stable up to 873 K. At that temperature the specific surface area value is 170 m(2)/g, and a CeO(2) cubic phase is identified together with ill-defined diffraction peaks tentatively assigned to Cu-Pd clusters, suggesting that the active phase is well dispersed over the support. Infrared studies prove that methanol conversion takes place over the catalyst to a high extent yielding syngas as main product in the range 473-723 K and methane at higher temperatures. Oxygenated intermediates containing methoxy, carbonile or formiate species are not detected, which evidences that methanol conversion to methane very probably takes place according to a via-carbide mechanism.
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad de Salamanca, Salamanca, Spain. vsescrib@usal.es
authors.forename: V
authors.initials: V
authors.lastname: Sánchez Escribano
authors.forename: C
authors.initials: C
authors.lastname: del Hoyo Martínez
authors.forename: A
authors.initials: A
authors.lastname: Castro Baz
authors.forename: J M
authors.initials: JM
authors.lastname: Gallardo Amores
authors.forename: E
authors.initials: E
authors.lastname: Fernández López
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D008697:Methane / Q000737:chemistry; D000432:Methanol / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002563:Cerium; D000536:Aluminum Hydroxide; D010165:Palladium; C030583:ceric oxide; C069471:aluminum oxide hydroxide; D003300:Copper; D000537:Aluminum Oxide; D008697:Methane; D000432:Methanol