Cascade NH 3 Oxidation and N 2 O Decomposition via Bifunctional Co and Cu Catalysts.

The selective catalytic oxidation of NH 3 (NH 3 -SCO) to N 2 is an important reaction for the treatment of diesel engine exhaust. Co 3 O 4 has the highest activity among non-noble metals but suffers from N 2 O release. Such N 2 O emissions have recently been regulated due to having a 300× higher greenhouse gas effect than CO 2 . Here, we design CuO-supported Co 3 O 4 as a cascade catalyst for the selective oxidation of NH 3 to N 2 . The NH 3 -SCO reaction on CuO-Co 3 O 4 follows a de-N 2 O pathway. Co 3 O 4 activates gaseous oxygen to form N 2 O. The high redox property of the CuO-Co 3 O 4 interface promotes the breaking of the N-O bond in N 2 O to form N 2 . The addition of CuO-Co 3 O 4 to the Pt-Al 2 O 3 catalyst reduces the full NH 3 conversion temperature by 50 K and improves the N 2 selectivity by 20%. These findings provide a promising strategy for reducing N 2 O emissions and will contribute to the rational design and development of non-noble metal catalysts.