Cascade NH3 Oxidation and N2O Decomposition via Bifunctional Co and Cu Catalysts

• Published in: ACS catalysis 2023-10, Vol.13 (20), p.13816-13827
• Main Authors: Guan, Xuze, Asakura, Hiroyuki, Han, Rong, Xu, Siyuan, Liu, Hao-Xin, Chen, Lu, Yao, Zhangyi, Yan, Jay Hon Cheung, Tanaka, Tsunehiro, Guo, Yuzheng, Jia, Chun-Jiang, Wang, Feng Ryan
• Format: Article
• Language: English
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.3c02392

The selective catalytic oxidation of NH3 (NH3–SCO) to N2 is an important reaction for the treatment of diesel engine exhaust. Co3O4 has the highest activity among non-noble metals but suffers from N2O release. Such N2O emissions have recently been regulated due to having a 300× higher greenhouse gas effect than CO2. Here, we design CuO-supported Co3O4 as a cascade catalyst for the selective oxidation of NH3 to N2. The NH3–SCO reaction on CuO–Co3O4 follows a de-N2O pathway. Co3O4 activates gaseous oxygen to form N2O. The high redox property of the CuO–Co3O4 interface promotes the breaking of the N–O bond in N2O to form N2. The addition of CuO–Co3O4 to the Pt–Al2O3 catalyst reduces the full NH3 conversion temperature by 50 K and improves the N2 selectivity by 20%. These findings provide a promising strategy for reducing N2O emissions and will contribute to the rational design and development of non-noble metal catalysts.