Enhanced alkali resistance of sulfated CeO2 catalyst for the reduction of NOx from biomass fired flue gas

Pristine CeO2 is not active for the selective catalytic reduction of NOx with NH3 (NH3-SCR) and the SCR activity is nearly totally lost due to the introduction of K. However, sulfation treatment of CeO2 leads to significantly improved SCR activity and remarkable resistance towards K poisoning. In-situ DRIFTS results revealed that the addition of K seldom affects the adsorption of NH3 over sulfated CeO2, whereas the adsorption of NH3 becomes very weak in the case of K-doped CeO2. The noticeably improved Brønsted acid sites due to the sulfation are responsible for the enhanced alkali resistance of sulfated CeO2 catalyst.