Catalytic oxidation of gas-phase mercury over Co/TiO2 catalysts prepared by sol–gel method

Co/TiO2 catalysts prepared by sol–gel method were studied for gas-phase mercury oxidation in this paper. Experimental results revealed that the optimal loading of Co was 7.5%, which yielded more than 90% oxidation efficiency within the temperature range of 120–330 °C. The high activity was mainly attributed to the enrichment of well dispersed Co3O4. We also found that oxygen performed a key role in mercury oxidation process, while HCl could corrode the oxidized mercury and release it to gas phase. Thereafter, a modified Mars–Maessen mechanism was proposed and the possible simultaneous oxidization of NO and mercury was studied.

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► 7.5% Co/TiO2 catalysts had a Hg oxidation efficiency of over 90% at120-330 °C.
► NO and Hg0 could be simultaneously oxidized, and Hg0 oxidation was superior to NO.
► O2 performed a key role in Hg0 oxidation, while HCl made Hg2+ release to gas phase.