Enhanced La0.875Ce0.125CoO3 catalyst for Hg0 removal from low-temperature flue gas: H2O and SO2 resistance performance and mechanism

The catalysts utilized for low-temperature catalytic oxidation of Hg 0 from flue gas typically suffer from issues related to H 2 O and SO 2 poisoning. This study focused on doping modification of La 0.875 Ce 0.125 CoO 3 perovskite with promoters and conducted a thorough investigation on the H 2 O and SO 2 resistance through characterization and DFT methods. Experimental results demonstrated that the LCeCO/30 wt% ZrO 2 possessed optimal H 2 O and SO 2 resistance. Under high sulfur (1500 ppm SO 2 ) and high humidity (10 % H 2 O(g)) conditions, it maintained approximately 91 % Hg 0 removal efficiency after thermal regeneration cycles. Characterization results indicated that ZrO 2 doping facilitated the formation of three-dimensional macroporous structure and protected active Co 3+ sites on the surface. Based on DFT calculations, the H 2 O poisoning is attributed to competitive adsorption between H 2 O(g) and Hg 0 on the active sites. Also, the SO 2 poisoning occurs due to competitive adsorption of SO 2 and the toxicity of sulfates to the surface active sites. Meanwhile, ZrO 2 doping can lower the adsorption energies of H 2 O(g) and SO 2 by modifying their adsorption configuration, thus weakening the competitive adsorption of H 2 O(g) and SO 2 with Hg 0 . Overall, LCeCO/ZrO 2 is a promising Hg 0 removal catalyst with superior H 2 O and SO 2 resistance.