Oxygen vacancies modulation: Visible light elimination of tetracycline and rhodamine B by surface defect-rich 3D rambutan-like hollow TiO2

Abstract

Organic contaminants in the water environment and liquid foods have posed a great threat to the environment as well as human well-being, and the low catalytic activity of traditional TiO2 photocatalysts limits its further application. Here, inspired by nature, a novel hydrogenated rambutan-like hollow TiO2 (denoted as HRT) was synthesized by facile hydrothermal treatment and in-situ hydrogenation reduction steps. The protruding spikes on the surface of the 3D rambutan-like hollow structure build a fast channel for charge transfer, the suitable cavity enhances light scattering and collection. The available inner/outer surface can bind contaminants more rapidly which facilitates transportation of photo-generated electrons. Relying on its special structure and abundant surface defects, HRT exhibits excellent photocatalytic degradation property. Under visible light irradiation, the photodegradation rate of rhodamine B (RhB) by HRT nearly reached 100.0%, and 80.0% for tetracycline (TC) within only 10 min, whose photocatalytic activity was 6.45 and 2.08 times higher than that of RT, respectively. Moreover, the innovative and practical application of HRT to the degradation of TC in milk revealed favorable degradation efficiency (71.0%) and salient catalytic reusability after five cycles. This work provides a new perspective on the purification of multiple organic contaminants in aqueous systems, points the way to the intractable problem of removing antibiotics from liquid foods and expands the application fields of semiconductor photocatalysts.