Copper supported on mixed alumina/gallium oxide pillared α-tin phosphate for De-NOx applications

Abstract

Alumina- and mixed alumina/gallium oxide-pillared α-tin phosphate have been impregnated with different amounts of copper via the incipient wetness method. Their characterization by X-ray photoelectron spectroscopy, H₂ temperature-programmed reduction and NO temperature-programmed desorption has allowed to gain insight into the nature of the copper species. These are present as small CuO clusters (not detectable by XRD) as well as forming part of spinel-like structures. NO-TPD studies show that only NO is desorbed from all the catalysts. Ga₃Al₁₁-SnP with 4.9 wt% Cu interacts most strongly with NO and this catalyst exhibits the highest degree of reduction of Cu²⁺ to Cu⁺ after the catalytic reaction. The catalysts are active for the selective catalytic reduction (SCR) of nitric oxide with propane in the presence of excess oxygen.