Synthesis, characterisation and behaviour of Co/hydroxyapatite catalysts in the oxidation of 1,2-dichloroethane

• Series of cobalt supported on hydroxyapatite catalysts are synthesised and characterised.
• Three types of cobalt species are detected in the prepared catalysts.
• The Co catalysts have been successfully tested in the oxidation of 1,2-dichloroethane.
• The Co(x)/hydroxyapatite catalysts achieve higher activity compared to bulk Co3O4.
• The distribution of Co species plays a decisive role in the activity and selectivity.

Calcium-deficient hydroxyapatite (HAP) loaded with different amounts of cobalt are synthesised and characterised by several techniques including N2 physisorption, XRD, TEM, H2-TPR, UV–vis-NIR DRS, XPS spectroscopy and volumetric adsorption of CO2 and NH3 molecules techniques. The Co(x)/HAP catalysts are tested in the oxidation of 1,2-dichloroethane. Due to significant enhancement of the textural and structural properties the resulting Co/hydroxyapatite catalysts achieve higher activity compared to bulk Co3O4 catalyst confirming the advantage of dispersing cobalt on a relatively high surface area HAP. Hydroxyapatite support shows a high selectivity towards intermediate reaction products; but its activity suffers a significant decay with time due to chlorination. However, high stability and high selectivity towards deep oxidation products are favoured by Co-rich catalysts.

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