Oxygen vacancy defects engineering on Cu-doped Co3O4 for promoting effective COS hydrolysis

Abstract

The activation of H2O is a key step of the COS hydrolysis, which may be tuned by oxygen vacancy defects in the catalysts. Herein, we have introduced Cu into Co3O4 to regulate the oxygen vacancy defect content of the catalysts. In situ DRIFTS and XPS spectra reveal that COS and H2O are adsorbed and activated by oxygen vacancy. The 10 at% Cu doped Co3O4 sample (10CuCo3O4) exhibits the optimal activity, 100% of COS conversion at 70 °C. The improved oxygen vacancies of CuCo3O4 accelerate the activation of H2O to form active OH. COS binds with hydroxyl to form the intermediate HSCO2−, and then the activated –OH on the oxygen vacancy reacts with HSCO2− to form HCO3−. Meanwhile, the catalyst exhibits high catalytic stability because copper species (Cu+/Cu2+) redox cycle mitigate the sulfation of Co3O4 (Co2+/Co3+). Our work offers a promising approach for the rational design of cobalt-related catalysts in the highly efficient hydrolysis COS process.