Characterization and deNO _x activity of copper-hydroxyapatite catalysts prepared by wet impregnation

Abstract

Copper loaded hydroxyapatite catalysts have been prepared by wet impregnation and have been tested in the selective catalytic reduction of NO by NH₃. The catalyst characterization showed the presence of copper oxide nanoparticles entrapped in the mesoporous matrix thus obstructing the Ca-Hap channel apertures. With increasing copper loading, there is a deposition of copper oxide clusters, on the surface of the carrier, containing Cu²⁺ and Cu⁺ ions. Compared to the catalyst prepared by the ion exchange method, Cu(1.12)Hap_i.e, which exhibited excellent NO conversion over a broad temperature range, the impregnated catalysts are less efficient in the selective catalytic reduction of NO by NH₃.