Nanosized ZnIn2S4 supported on facet-engineered CeO2 nanorods for efficient gaseous elemental mercury immobilization.

Abstract

Nanosized ZnIn2S4 supported on facet-engineered CeO2 nanorods were prepared by solvothermal method to effectively capture gaseous elemental mercury from flue gas. The CeO2/ZnIn2S4 sorbent exhibited excellent mercury removal performance (>90%) in a wide temperature range from 60 to 240\xa0℃ and showed much higher mercury adsorption capacity than pure CeO2 due to the enlarged specific surface area and abundant active oxygen and sulfur sites on the surface. It was found that CeO2/ZnIn2S4 has good resistance to SO2, NO and H2O. At the optimal 120\xa0℃, the equilibrium Hg0 adsorption capacity of CeO2/ZnIn2S4 can reach 19.172\xa0mg/g, which is superior to the reported series of benchmark materials. X-ray photoelectron spectroscopy and temperature programmed desorption of mercury confirmed that the adsorbed mercury existed on the surface as HgO and HgS, indicating that catalytic oxidation and chemisorption occurred on the surface of the adsorbent. The adsorption energy of Hg0 on the CeO2 (110) and ZnIn2S4 (110) surfaces calculated with density functional theory (DFT), further confirms that the surface activated oxygen and sulfur sites are the most stable adsorption sites. Furthermore, the good regeneration capability of CeO2/ZnIn2S4 makes it more promising for Hg0 capture in practical applications.