Self-assembled CoTiO3 nanorods with controllable oxygen vacancies for the efficient photochemical reduction of CO2 to CO

Abstract

Cobalt titanate (CoTiO₃) is a kind of semiconductor material with low catalytic activity, so it is seldom reported. In this work, a simple but effective method was utilized to generate oxygen vacancies on the surface of cobalt titanate. The surface oxygen vacancies were measured by XPS of O 1s and EPR spectroscopy. The presence of oxygen vacancies can not only improve the adsorption ability of CO₂, but also change the band structure of CoTiO₃, which facilitates the transfer of excited electrons from a photosensitizer to the cocatalyst. Theoretical calculations indicated that the formation of surface oxygen vacancies on CoTiO₃ could greatly enhance the binding strength of CO₂. Furthermore, the free energy needed to pass the rate-determining step was small during the catalytic process. As a result, the catalytic efficiency of CoTiO₃ with oxygen vacancies was nine times that of pristine CoTiO₃.