Abstract
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.