The roles of hydroxyapatite and FeOx in a Au/FeOx hydroxyapatite catalyst for CO oxidation

A FeOx-modified hydroxyapatite (HAP, Ca10(PO4)6(OH)2)-supported gold catalyst is highly active and stable during CO oxidation at low temperature, and it is also sinter-resistant to calcination at temperature up to 600 °C. This work used catalyst characterization and activity tests to investigate the roles of the HAP support and FeOx promoter in CO oxidation. XPS results suggested that a strong interaction between the HAP support and the Au and FeOx nanoparticles gave the sintering resistance. In situ DRIFT studies revealed that the addition of FeOx changed the nature of the reaction mechanism and intermediates to promote catalytic activity. TEM and Mössbauer examination of the spent catalysts in combination with the in situ DRIFT results suggested that the better stability of Au/FeOx-HAP originated from its better prevention of carbonate accumulation.

The hydroxyapatite stabilizes gold and FeOx nanoparticles by a strong interaction with these, while FeOx promotes the catalytic activity by changing the nature of the reaction mechanism and the intermediates.Figure optionsDownload as PowerPoint slide