TAILIEUCHUNG - Báo cáo " Using the reduced La(Co,Cu)O3 nanoperovskites as catalyst precursors for CO hydrogenation "

A series of ground La(Co,Cu)O3 perovskite-type mixed oxides prepared by reactive grinding has been characterized by X-Ray diffraction (XRD), BET, H2-TPR, O2-TPD, and CO disproportionation. All ground samples show a rather high specific surface area and nanometric particles. The solids were pretreated under H2 atmosphere to provide a finely dispersed Co-Cu phase which is active for the hydrogenation of CO. | VNU Journal of Science Natural Sciences and Technology 25 2009 112-122 Using the reduced La Co Cu O3 nanoperovskites as catalyst precursors for CO hydrogenation Nguyen Tien Thao1 Ngo Thi Thuan2 Serge kaliaguine2 1 Faculty of Chemistry College of Science VNU 19 Le Thanh Tong Hanoi Vietnam Department of Chemical Engineering Laval University Quebec Canada. G1K 7P4 Received 07 December 2007 Abstract. A series of ground La Co Cu O3 perovskite-type mixed oxides prepared by reactive grinding has been characterized by X-Ray diffraction XRD BET H2-TPR O2-TPD and CO disproportionation. All ground samples show a rather high specific surface area and nanometric particles. The solids were pretreated under H2 atmosphere to provide a finely dispersed Co-Cu phase which is active for the hydrogenation of CO. The reduced perovskite precursors produced a mixture of higher alcohols and hydrocarbons from syngas following an ASF distribution. Keywords perovskite Co-Cu metals syngas alcohol synthesis. 1. Introduction Perovskites are mixed oxides with the general formula ABO3. In theory the ideal perovskite structure is cubic with the space-group Pm3m-Oh 1 . The structure can be visualized by positioning the A cation at the body center of the cubic cell the transitionmetal cation B at the cube corners and the oxygen at the midpoint of the cube edges. In this structure the transition-metal cation is therefore 6-fold coordinated and the A-cation is 12-fold coordinated with the oxygen ions. Moreover each of the A and B positions could be partially replaced by another element to prepare a variety of derivatives 1 2 . For example a partial substitution of La in Corresponding author. Tel. 84-4-39331605. E-mail nguyentienthao@ lanthanum-cobaltate by either Sr or Th has remarkably affected the rate of carbon dioxide hydrogenation 3 and methane oxidation 4 . The substitution of the cation at A-position however is much less attractive than that at B-site due to the usual lack of activity .

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