Reclaiming Ti-bearing blast furnace slag into wide-temperature and sulfur-resistant catalyst to boost flue gas demercuration

Elimination of neurotoxic mercury from coal-fired flue gas is imperative to the global environment. This work reclaimed waste Ti-bearing blast furnace slags (TBFS) into perovskite-type catalyst for efficient flue gas demercuration (DeHg). Through mild impregnation with Mn and Ce, the TBFS-based catalyst exhibited desirable DeHg performance at wide-range temperatures (50 ∼ 300 °C), good tolerance to varied SO₂ concentrations (400 ∼ 1200 ppm), and long-term DeHg stability (30 h, > 85 % DeHg efficiency) under typical coal-fired flue gas conditions, thereby outperforming existing Mn- and Ce-containing catalysts (perovskites, spinels, and other synthetic oxides). Mn-Ce interplay was well characterized to facilitate O₂ dissociation and mitigate SO₂ competition by modulating the redox activity of MnCe/TBFS catalyst. DFT calculations revealed in-depth that Hg⁰ oxidation over MnCe/TFBS was rate-determined by O₂ dissociation and significantly promoted by the activated oxygens. Our attempt herein has exemplified a feasible strategy to deal with waste slag disposal and Hg emission synergistically.