Selective Catalytic Reduction of Nitrogen Oxides with Carbon Monoxide over Zeolite-Supported Iridium Catalysts

Among the technologies for removing nitrogen oxide(NOx), which is known as a secondary-particulate-matter-inducing precursor, selective catalytic reduction by NH₃(NH₃-SCR) applied to car waste gas treatment has a disadvantage of supplying NH₃ by converting urea; thus, an alternative technology is required. Carbon monoxide(CO) is considered a good alternative because it can be easily supplied from fuels, directly from swept gas or through the engine technology. The CO-SCR technology has been studied in a limited range, and in particular, despite the use of zeolites as NH₃-SCR commercial catalysts, CO-SCR studies using these zeolites as support are hardly reported. In this study, CO-SCR catalysts were synthesized by impregnating iridium into various types of zeolite support, and the NOx conversion was evaluated according to the type of support. The synthesized catalysts were characterized via PXRD, TEM, N₂ sorption, and H₂ chemisorption.