CO oxidation using gold supported on Ce-Mn-O composite materials

• Type: Chapter or Part of a Book
• Date: 2012

Authors

Sónia Carabineiro (Author) FEUP; Silva, Adrian (Author) FEUP; Drazic, G. (Author) Other; Tavares, P.B. (Author) Other; José Luis Figueiredo (Author) FEUP

Book

Title: Carbon Monoxide: Sources, Uses and Hazards

Pages: 61-84

Indexing

Scopus

Other information

Abstract (EN): Carbon monoxide (CO) is a colourless, odourless, highly toxic, poisonous gas. Exposure to a few hundreds ppm can cause permanent health damages or even death. Low level exposure, if continued, can also cause health problems in the long term. CO can thus be considered as one of the most dangerous environmental pollutants. Therefore, its removal and detection is of extreme importance for safe living.Catalysts which promote CO oxidation at room temperature will find many practical applications that include air-purification devices for indoor space (including gas masks), and for cleaning automotive exhaust gases. CO removal is also required in CO2 lasers, and in polymer electrolyte fuel cell (PEFC) usage, where the CO concentration in the hydrogen rich gas must be selectively reduced to less than 100 ppm.Haruta and co-workers have intensively investigated the ability of gold catalysts to catalyse this reaction. In their early work in the 80s, the activity of supported gold catalysts came as a surprise, but it is now well known that supported gold nanocatalysts are effective for CO oxidation at very low temperatures, being active even at -70°C. However, activities depend on the choice of the metal oxide support.In the present work, Ce-Mn-O supports with different Ce/Mn ratios were prepared by co-precipitation, in addition to cerium oxide only and manganese oxide only. These supports were loaded with gold by a double impregnation method. Samples were characterised by adsorption of N2 at -196°C, temperature programmed reduction (TPR), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field imaging (HAADF) with Z-contrast. CO oxidation was studied using a continuous-flow reactor connected to a gas chromatograph.It was found that the higher the amount of ceria in the sample, the most active it was for CO oxidation. The ability to convert CO seems to be independent of the surface area of the supports, but seems to vary according to the temperature of the first reduction peak of the TPR spectrum, in the case of samples loaded with gold. Also it varies according to the gold nanoparticle size. © 2012 Nova Science Publishers, Inc. All rights reserved.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 24