Enabling Catalysts for Carbonyl Sulfide Hydrolysis

Carbonyl sulfide (COS), an organosulfur compound commonly present in industrial gases, poses significant challenges for environmental protection and industrial processes due to its toxicity. This paper reviews recent advancements in the development of catalysts for COS hydrolysis, emphasizing the effects of various supports and active components on catalyst performance, as well as the mechanisms underlying the hydrolysis reaction. Traditional supports like γ-Al2O3 demonstrate high activity for COS hydrolysis but are susceptible to deactivation. In contrast, novel supports such as activated carbon, TiO2, and ZrO2 have garnered attention for their unique structures and properties. The incorporation of active components, including alkali metals, alkaline earth metals, transition metals, and rare earth metals, significantly enhances the hydrolysis efficiency and resistance to deactivation of the catalysts. Additionally, this paper outlines three primary mechanisms for COS hydrolysis: the alkali-catalyzed mechanism, the Langmuir–Hinshelwood model, and the Eley–Rideal model mechanism, as well as the thiocarbonate intermediate mechanism, which collectively elucidate the conversion of COS into the H2S and CO2 catalyzed by these systems. Future research efforts will concentrate on developing high-activity, high-stability, and cost-effective COS hydrolysis catalysts, along with a more in-depth exploration of the reaction mechanisms to facilitate the efficient removal of COS from industrial emissions.