Role of Ceria in the Design of Composite Materials for Elemental Mercury Removal

Abstract

The necessity to drastically act against mercury pollution has been emphatically addressed by the United Nations. Coal‐fired power plants contribute a great deal to the anthropogenic emissions; therefore, numerous sorbents/catalysts have been developed to remove elemental mercury (Hg0) from flue gases. Among them, ceria (CeO2) has attracted significant interest, due to its reversible Ce3+/Ce4+ redox pair, surface‐bound defects and acid‐base properties. The removal efficiency of Hg0 vapor depends among others, on the flue gas composition and temperature. CeO2 can be incorporated into known materials in such a way that the abatement process can be effective at different operating conditions. Hence, the scope of this account is to discuss the role of CeO2 as a promoter, active phase and support in the design of composite Hg0 sorbents/catalysts. The elucidation of each of these roles would allow the integration of CeO2 advantageous characteristics to such degree, that tailor‐made environmental solution to complex issues can be provided within a broader application scope. Besides, it would offer invaluable input to theoretical calculations that could enable the materials screening and engineering at a low cost and with high accuracy.

CeO2-Decorated α-MnO2 Nanotubes: A Highly Efficient and Regenerable Sorbent for Elemental Mercury Removal from Natural Gas

“…The abundance of surface oxygen species has been repeatedly reported to improve Hg 0 removal efficiency, by providing the active sites for Hg 0 adsorption on the surface of sorbent/catalyst. 36 Finally, the O 1s and Mn 2p XPS spectra (Figure S6a,b) of the regenerated MnCe35 (see next sections) revealed that after the hightemperature regeneration process under N 2 atmosphere, the O b /O a and Mn 3+ /Mn 4+ ratios were reduced to 62.6 and 55.1%, respectively, possibly indicating, a favorable for Hg 0 removal, the correlation between the oxygen vacancies and the surfaceadsorbed oxygen species.…”

“…Consequently, the modification of a certain morphology of α-MnO 2 by means of ceria nanoparticle decoration can significantly improve its Hg 0 removal activity at room temperature. This is exciting given that there are many studies reporting Mn−Ce composite materials for Hg 0 removal, 36 however operating at high temperatures (>150 °C).…”

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

“…Nanosized ceria finds a large variety of applications [71], and extensive reviews exist on the topic, especially relevant to catalysis [1] for energy [72,73] and environmental preservation [74] and remediation [75,76]. Therefore, here we will focus on the latest advancements described in the most recent years, with an emphasis on biological applications, for which the use of biomolecular templates for ceria nanostructures' assembly is particularly relevant.…”

Enhanced activity and SO2 resistance of Co‐modified CeO2‐TiO2 catalyst prepared by facile co‐precipitation for elemental mercury removal in flue gas

“…A variety of transition metal oxide catalysts for mercury oxidation, such as Mn, Cu, Fe, V, Ce and Co, have been employed in experiments. Ce‐based catalyst is regarded as one of the best candidates for Hg 0 oxidation removal with O 2 as the oxidant due to its active and facile Ce 3+ /Ce 4+ redox cycle and the corresponding outstanding oxygen storage capacity .…”