Nitrogen-doping boosted the activity of K/Al2O3 catalysts in simultaneous removal of COS and CS2: An experimental and theoretical study

The simultaneous catalytic purification of COS and CS2 in blast furnace gas usually suffers from poor removal activity, and a molecular understanding of the reaction mechanism over typical Al-based catalysts is still missing. Herein, we reported that N-doping was an effective strategy to enhance the activity of K0.1Al2O3. The optimal N-doped K0.1Al2O3 achieved more than 95% COS and CS2 conversion, with 80% H2S selectivity at 150 °C. It was revealed that N-modification promoted the formation of N-Al, oxygen vacancies and OH- species, and induced stronger basic sites. Besides, the N-doping enhanced COS and CS2 adsorption, and facilitated the formation of reactive intermediate species. The adsorbed CS2 combines with H to produce CS2H-, which further reacts with H- or OH- and triggers the cleavage of the C-S bond to produce H2S and COS. The introduction of N changes the process of C-S bond cleavage and reduces the reaction energy barrier.