Characterization of an AgCl/Al2O3 catalyst for lean NO conversion
Abstract
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 ∽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 ∽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.