Remarkable N 2 selectivity enhancement of NH 3 -SCO reactions over V 0.5 /Pt 0.04 /TiO 2 catalyst through Cu-Er co-modification.

Pt-V bimetallic catalysts maybe promising substitutes to precious metal catalysts for selective catalytic oxidation (SCO) of NH 3 . But it remains a major challenge for Pt-V bimetallic catalysts to pursue high NH 3 conversion rate and N 2 selectivity simultaneously. In this work, both Cu and Er were adopted to modify V 0.5 /Pt 0.04 /TiO 2 catalyst (denoted as V/PT), and the influences of Cu and Er doping amounts on NH 3 -SCO performance of V/PT catalysts were investigated systematically. The results indicated that the co-modification of Cu and Er imposed little influence on NH 3 conversion efficiency, but significantly boosted N 2 selectivity. Compared with other Cu-Er-modified V/PT catalysts, CEV/PT-4 catalyst exhibited outstanding NH 3 -SCO performance, which attained completely 100% NH 3 conversion efficiency and > 90% N 2 selectivity in the temperature range of 225-450 °C. It was significantly superior to the NH 3 -SCO performance of most previously reported catalysts. The characterization results indicated that the adequate doping amounts of Cu and Er resulted in an obvious enhancement on redox property and surface acidity of CEV/PT-4 catalyst. It also led to abundant Pt 0 and surface chemisorbed oxygen species on catalyst surface, which facilitated the oxidation of NH 3 to NO x and enhanced i-SCR reactions. In situ DRIFTS results showed that -NH 2 species on the surface of CEV/PT-4 catalyst could actively react with nitrate species to generate N 2 and H 2 O.