New insight into binary TiO₂@C nanocomposites: the crucial effect of an interfacial microstructure

Combining with carbon materials is a common and efficient strategy to improve the photocatalytic performance of TiO₂. But the fundamental nature of the interfacial microstructures between carbon and TiO₂ and how they affect the photocatalysis process remain controversial. In this work, hybrid TiO₂@C nanocomposites with different carbon contents are synthesized. It is found that an interfacial disorder region with interfacial Ti-O-C bonds and abundant defects (oxygen vacancies, V_O) can be generally formed from the chemical interactions between carbon and Ti-O-Ti skeletons. These interfacial V_O sites are well stabilized by the carbon complex coating, and maintain their intrinsic nature in visible light absorption and electron trapping. Moreover, the synergistic effect of interfacial bonding, defective sites and the components on the visible photocatalysis of TiO₂@C composites has been carefully investigated, and a corresponding mechanism is also proposed.