Fe–Ce Mixed Oxides Supported on Carbon Nanotubes for Simultaneous Removal of NO and Hg⁰ in Flue Gas

Developing simultaneous removal technology of NO_x and Hg⁰ in flue gas is highly desirable but remains challenging. Multiwalled carbon nanotube supported Fe–Ce mixed oxide nanoparticles (Fe₍₂₎Ce_(0.5)O_x/MWCNTs) were prepared using the ethanol impregnation method for DeNO_x and Hg⁰ removal. The NO and Hg⁰ removal efficiencies over catalyst reached to 99.1% and 88.9% at 240 °C and a space velocity of 30 000 h^–1. The Fe–Ce mixed oxides supported both inside and outside of MWCNTs in highly dispersed form with particle size of 3–5 nm. The Ce⁴⁺ existed on MWCNTs in two forms, some of which are the fluorite-like crystal CeO₂; the other portion of Ce⁴⁺ entered the spinel structure of γ-Fe₂O₃ and led to the distortion of the γ-Fe₂O₃ lattice. Furthermore, it is evident that the chemisorbed oxygen content and oxidation activity of catalysts increased dramatically after Ce doping, which could be attributed to the excellent NH₃-SCR and Hg⁰ removal performance.