Engineering regulation of oxygen vacancies and hydroxyl oxygen groups for low-temperature catalytic hydrolysis of carbonyl sulfide

The deep purification of carbonyl sulfide (COS) is crucial for improving natural gas utilization and promoting environmental sustainability. In this study, a series of modified Cu-Zr/ZnAlOx catalysts was synthesized for COS catalytic hydrolysis, and the regulatory mechanisms of alkali modification and nitrogen doping were systematically investigated. Alkali modification promotes COS hydrolysis and H 2 S oxidation by converting Cu + to Cu 2+ (reducing oxygen vacancies), transforming hydroxyl groups into ·OH, and catalyzing ·O 2 - to 1 O 2 (accelerating the oxidation of H 2 S and elemental sulfur). Nitrogen doping inhibits the direct conversion of H 2 S/elemental sulfur to SO 2 (enhancing oxidation selectivity) by promoting lattice oxygen-to-adsorbed oxygen conversion (increasing oxygen vacancies), forming metal-nitrogen bonds (M–N, conducive to ·OH generation), and suppressing ·O 2 - to 1 O 2 conversion. The synergistic effect of alkali modification and nitrogen doping enhances H 2 O dissociation and C–S bond cleavage during COS hydrolysis, while improving the selectivity of H 2 S oxidation to elemental sulfur. This work provides new insights into the synergistic regulation of dual modifications for efficient COS catalytic hydrolysis. The synergistic effect of alkali modification and nitrogen doping on the COS hydrolysis process is reflected in the dissociation of H 2 O and the cleavage of C–S bonds. • Alkali modification results in the conversion of Cu + to Cu 2+ . • M-N bonds promote the generation of adsorbed oxygen and hydroxyl radicals. • The synergistic effect promotes the dissociation of H 2 O and the cleavage of C–S bonds. • 1 O 2 is the primary factor in H 2 S oxidation, and ·O 2 - can be converted into 1 O 2 . • Alkali modification and nitrogen doping promotes and inhibits the conversion of ·O 2 - to 1 O 2 respectively.