Copper manganese based mixed oxides for ambient temperature co-oxidation and higher temperature oxidation reactions

Cole, Kieran John 2008. Copper manganese based mixed oxides for ambient temperature co-oxidation and higher temperature oxidation reactions. PhD Thesis, Cardiff University.

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Abstract

The catalytic oxidation of carbon monoxide is an important reaction in heterogeneous catalysis. Copper manganese mixed oxides in the form of Hopcalite, CuMn₂C₄, is used as a catalyst for the oxidation at ambient temperature and is important in respiratory protection, particularly in mining industries. These types of catalysts are prepared by a co-precipitation method variables in this preparation procedure are known to control catalytic activity. Previous work has shown that the addition of a cobalt dopant metal to the catalyst structure can have a positive effect on activity towards CO oxidation. This thesis furthers the work of dopant addition by studying the effects of zinc on the copper manganese catalyst. Catalyst testing for CO oxidation showed that the addition of the zinc dopant metal increases the stability of catalytic activity. Temperature Programmed Reduction studies show that the addition of zinc has an effect on the redox properties of the catalyst. Prepared copper manganese oxide catalysts were used as supports for gold catalysts. Gold supported CuMnOx was prepared by a deposition precipitation method. The addition of gold to these active materials leads to a marked increase in the catalytic activity. Scanning Electron Microscopy (SEM) showed that the morphology of the support used, played an important role in producing a highly active catalyst. Also, the ageing time of the catalyst precursor was shown to influence catalytic activity. The most effective catalyst for CO oxidation was found to be a 1 wt% Au supported catalyst. The presence of moisture in the gas feed is known to be detrimental to a Hopcalite catalyst for ambient temperature CO oxidation. The effect of moisture on the copper manganese mixed oxide catalysts highlighted the improvement in moisture tolerance with the addition of gold. The method of depositing gold onto an oxide support was shown to be applicable to a commercially available catalyst. The gold supported CuMnOx catalysts prepared were tested for oxidation reactions at higher temperatures. The reactions investigated were ethylene oxide oxidation and preferential oxidation (PROX) of carbon monoxide. Studies showed the addition of gold to the CuMnOx catalysts, improves activity compared to an undoped catalyst.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
ISBN:	9781303212895
Date of First Compliant Deposit:	30 March 2016
Last Modified:	09 Jan 2018 23:58
URI:	https://orca.cardiff.ac.uk/id/eprint/54689

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