Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10241498 | Applied Catalysis B: Environmental | 2005 | 10 Pages |
Abstract
Commercially available black pigment consisting of mixed manganese, copper and iron oxides was tested as a catalyst as well as an oxidant for CO oxidation. The crystalline structures of the catalyst were determined by XRD as Cu1.5Mn1.5O4 mixed with Fe2O3 and Mn3O4 oxides. The fresh catalyst with 30-300 nm size and a BET surface area of 18.5 m2 gâ1 was able to completely convert CO at 525 °C even at a significantly high COO2He gas flow rate of 1000 ml minâ1 (corresponding space velocity being â¼310,000 hâ1). While the reaction rate was independent of oxygen concentration in the range tested (0.8-9.9 vol.% of O2 at a constant CO concentration of 0.85%), it depended on CO concentration. The reaction order over fresh catalyst was measured to be 0.85 with respect to CO with an activation energy value of 47.9 kJ molâ1. Application of a reduction followed by oxidation type of heat treatment on fresh catalyst induced the formation of fine clusters or domains of â¼5 nm on the surface of the catalyst particles. This refined morphology with high density of defects led to a great improvement in catalytic activity. Complete CO conversion was achieved at 180 °C over a heat treated catalyst. This change in morphology also led to higher reducibility of mixed oxide system after heat treatment as indicated by TPR results. The mixed oxides of transition metals can be a viable alternative to precious metal and noble metal containing catalysts for oxidation of CO.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Catalysis
Authors
S. PalDey, S. Gedevanishvili, W. Zhang, F. Rasouli,