Raman spectroscopic studies of selective catalytic reduction (SCR) catalysts

Raman spectroscopy has gained acceptance for a wide variety of industrial applications over the past several years as a result of significant advances in instrumentation. Although Raman and infrared (IR) spectroscopy are considered to be complementary techniques in terms of the information they provide, Raman spectroscopy has some characteristics that make it ideally suited for certain types of analyses which are not as readily amenable to examination using IR spectroscopy. This presentation will focus on the practical applications of using Raman spectroscopy as an in situ technique to monitor the molecular structure changes of catalytically-active metal oxides dispersed upon a support material during calcination. A variety of vanadium oxide catalysts were studied to determine the relationship between vanadium structure and reactivity for the Selective Catalytic Reduction (SCR) of nitric oxide by ammonia. The effects of vanadium oxide coverage, moisture, surface sulfate species, oxide support, and a second dispersed oxide phase on SCR activity will be addressed.