Characterization of an AgCl/Al2O3 catalyst for lean NO conversion

An AgCl/Al2O3 catalyst calcined at 873 K in air is highly active for the conversion of lean NO with ethanol even in the presence of SO2. The chemical and physical characteristics of the AgCl/Al2O3 catalyst were studied using X-ray diffraction, X-ray photoelectron spectroscopy and ultraviolet-visible (UV-VIS) spectroscopy. Crystallized AgCl particles were formed for the AgCl/Al2O3 catalyst calcined above 393 K in air. AgCl particles began to disperse on the Al2O3 surface upon calcination at 773 K. Dispersion of the AgCl particles progressed upon calcination at 873 K. UV-VIS spectra also showed an intense absorption band at similar to 250 nm for the AgCl/Al2O3 catalyst calcined at 873 K which can be attributed to the AgCl on Al2O3. Surface silver content in the AgCl/Al2O3 catalyst calcined at 873 K is similar to 4.2 times that of the AgCl/Al2O3 catalyst calcined at 773 K. These results suggest that effective NO conversion over the AgCl/Al2O3 catalyst calcined at 873 K in air is ascribed to the AgCl particles being well dispersed by interaction with Al2O3.