Activated oxygen species in CeO2 nanorod supported MnOX from metal oxide-support interaction to boost Hg0 removal from flue gas

Developing efficient and low-cost transition metal oxide sorbent for Hg⁰ removal is crucial to mercury abatement from flue gas. Herein, MnO_X was loaded onto CeO₂ with different morphologies (cube, rod and particle) to prepare the Mn-Ce sorbents. MnO_X supported by CeO₂ nanorod (Mn-Ce_r) can achieve the best Hg⁰ removal performance due to its high specific surface area, prominent redox capacity, enhanced surface acidity and activated oxygen species (lattice and chemisorbed oxygen). Additionally, the strong interaction of highly dispersed Mn species with CeO₂ nanorod carrier weakens the metal-oxygen bond strength and enhances the interfacial electron transfer, thereby leading to more oxygen vacancies and increasing surface reactive oxygen species over Mn-Ce_r. The density functional theory (DFT) calculations further indicate the formation of Mn-O-Ce bond and oxygen vacancies over Mn-Ce_r in which Hg atom can be chemically bound to O sites to form Hg-O. Under 5 % O₂, 500 ppm NO, 800 ppm SO₂ and 3 % H₂O, Mn-Ce_r can still achieve a satisfactory Hg⁰ removal performance (88.1 %), suggestive of its good adaptability under complicated flue gas conditions and application prospect.