A novel highly active catalyst form CuFeMg layered double oxides for the selective catalytic reduction of NO by CO

• Published in: Fuel (Guildford) 2022-06, Vol.317, p.123469, Article 123469
• Main Authors: Liu, Jun, Zang, Pengchao, Liu, Xiaoqing, Mi, Jinxing, Wang, Ying, Zhang, Guojie, Chen, Jianjun, Zhang, Yongfa, Li, Junhua
• Format: Article
• Language: English
• Subjects: Carbon monoxide; Catalysts; Catalytic activity; Chemical reduction; CO-SCR; Composite materials; Copper; Cu-based catalysts; High temperature; Hydroxides; Iron; Layered double hydroxide; Low temperature; Mechanism; Metal oxides; Oxygen; Reactive oxygen species; Selective catalytic reduction
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2022.123469

•Cu doping can enhance the low temperature performance of CO-SCR reaction.•Cu1.2FeMg2.8-LDO catalyst exhibited an outstanding stability and water resistance.•The strong synergy between Cu and Fe plays a key role in the CO-SCR reaction.•The CO-SCR reaction mechanism was proposed based on in situ DRIFT spectra and NAP-XPS. A series of CuxFeMg4-x-LDO and Cu/FeMg2.8-LDO catalysts were prepared by calcination of CuFeMg layered double hydroxide (LDH) for CO-SCR reaction. The Cu1.2FeMg2.8-LDO catalyst exhibited the highest CO-SCR activity and the NO conversion reach 100 % at 225–600 °C with a space velocity of 60000 mL·g−1·h−1. The CuxFeMg4-x-LDO composite metal oxide generated by topotactic transformation not only promotes the dispersion of CuO species but also promotes the generation of CuzMg1-zFe2O4 spinel phase and the reactive oxygen species (Cu2+-O-Cu2+ and Cu2+-O-Fe3+). Moreover, it also has the high H2 consumption and more surface adsorbed oxygen, which can significantly improve the redox capacity of the catalysts. The appearance of Cu+–CO/Fe2+–CO species and the relatively low activation energy are also responsible for the better catalytic activity of Cu1.2FeMg2.8-LDO at low temperatures. Furthermore, for the CO-SCR reaction over Cu1.2FeMg2.8-LDO catalysts, the L-H mechanism is consistent at low temperatures and the E-R mechanism at high temperatures. This work offers insights for the rational design of highly efficient catalysts for the low temperature CO-SCR reaction.