Kinetics of the Hopcalite‐catalyzed oxidation of carbon monoxide

Abstract

The oxidation of carbon monoxide with Hopcalite catalyst was studied in an isothermal recycling reactor with special attention poid to the changes of gas phase compositions with time.Conversion-time data exhibit significant departures from first-order behavior often ascribed to this reaction. In early stages the reaction rate declines more rapidly than would a first-order reaction; later the reverse is true. A mechanism, based on careful analyses of the literature and of our observations, is proposed. A kinetic model based on this mechanism is shown to reproduce the data of any run satisfactorily, but there is a considerable variation in values of the constants from run to run.

Metal-Based Composite Nanomaterials

“…Before Haruta's discovery, the catalysts for CO oxidation are hopcalite catalysts (mixed oxides mainly composed of Mn and Cu) or noble metals, e.g., platinum or palladium. However, these catalyses, although have high catalytic activities, are either not water tolerant or not sufficiently active at ambient temperature or in the presence of concentrated CO (Brittan et al 1970;Bond et al 1975;Desai et al 1983;Dauchot and Dath 1984). The novel gold catalysts employed by Haruta and coworkers were prepared by coprecipitation from an aqueous solution of chloroauric acid and the nitrate of transition metals.…”

Ambient Temperature CO Oxidation Using Palladium–Platinum Bimetallic Catalysts Supported on Tin Oxide/Alumina

“…Catalytic carbon monoxide oxidation is one of the simplest oxidation reactions, but it has been extensively studied due to the numerous environmental and industrial applications [1][2][3]. Hopcalite catalysts, comprising copper and manganese oxides, are widely utilised for CO oxidation due to their excellent activity at ambient temperatures and low cost [4,5], although they can be sensitive to water vapour and thus prone to deactivation in the presence of moisture [6]. Supported platinum group metals (PGMs) are highly active in catalytic oxidation reactions [7][8][9][10], exhibiting activity for CO oxidation at ambient temperatures; however, the PGM content should be minimised due to the high cost and tendency for CO self-poisoning [11,12].…”

Catalytic combustion of SOFC stack flue gas over CuO and Mn2O3 supported by La0.8Sr0.2Mn0.67Cu0.33O3 perovskite

“…According to Cullen et al, a combination of Pd‐Pt and Cu‐Mn‐oxides catalysts arranged in series can completely oxidize CO, H 2 , and CH 4 at temperature above 650°C . Hopcalite, which is a group of amorphous Cu‐Mn oxides, has been widely used as oxidation catalyst to remove CO and volatile organic compounds . However, these catalysts have a deactivation problem when they are exposed to the temperature above 650°C .…”