Facile Construction of Carbon Dots Layer and Oxygen Vacancies Simultaneously onto TiO2 to Enhance Photoreduction Activity

Abstract

Main observation and conclusionWe reported a facile and green hydrothermal strategy to tailor the carbon dots layer (CDL) and oxygen vacancies (Vo) modified on TiO2, by using ascorbic acid as CDL precursor and Vo regulator. The amorphous CDL was uniformly coated on the surface of the as prepared CDL@TiO2–x composites by Ti‐O‐C bond. With the increase of carbon content, the amorphous CDL gradually became thicker, while the Vo concentration first increased and then decreased. 1.5 CDL@TiO2–x possessed the highest Vo concentration. With the decoration of CDL and Vo, the photoreduction properties of CDL@TiO2–x composites were significantly improved. Under simulated solar light and visible light, the reaction rates of 1.5 CDL@TiO2–x were 9.6 times and 216 times higher than that of pure TiO2, respectively. Interestingly, the results discovered that CDL and Vo influenced the properties of CDL@TiO2–x composites in different ways. The primary function of CDL was to improve the utilization of solar light, and the enhancement of the charge transfer ability was decided by Vo and CDL together. Our work provides a new strategy for the modification of TiO2 and sheds new light on the respective role of CDL and Vo when they coexist in the catalyst.