Highly facile Co2+ and Mn3+ species supported on hydroxyapatite catalyst for carbon monoxide oxidation at a lower temperature

The series of bimetallic Co and Mn supported on hydroxyapatite (HAp) catalysts were prepared by successive deposition method and examined for CO oxidation. The catalysts are characterized in detail and correlated to oxidation activity. The X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed reduction characterization showed the presence of more facile Co2+, Mn3+ and adsorbed oxygen. The attenuated total reflection-Fourier transform infrared demonstrated the adsorption of water on active sites of catalyst was responsible for the shifting of activity towards higher temperatures. The Co0.4/Mn0.1/HAp catalyst showed lower activation energy for CO oxidation compared to the monometallic catalysts. Interaction between Mn, Co and HAp could be responsible for the existence of Co2+, Mn3+ and adsorbed oxygen, which are active species for CO oxidation.