Fourier-transform infrared studies of copper-containing Y zeolites. Dehydration, reduction and the adsorption of ammonia

Abstract

The reduction of Cu^II to Cu^I ions in partially Cu^II-exchanged zeolite Y by CO plus co-adsorbed NH₃ has been studied (298–673 K) using Fouriertransform infrared spectroscopy. While the data are complex the formation of a variety of species including [Cu(NH₃)]²⁺, [CuCO(NH₃)_n]⁺, NH⁺₄ and hydrogen-bonded NH₃ have been identified. The data indicate that at low temperature reduction by NH₃ is dominant while at elevated temperature CO is a more important reducing agent.