Facile Synthesis of GdF3:Yb3+, Er3+, Tm3+@TiO2–Ag Core–Shell Ellipsoids Photocatalysts for Photodegradation of Methyl Orange Under UV, Visible, and NIR Light Irradiation

Abstract

To enhance solar energy utilization efficiency, goal-directed design of architectures by combining nanocomponents of radically different properties, such as plasmonic, upconversion, and photocatalytic properties may provide a promising method to utilize the most energy in sunlight. In this work, a new strategy was adopted to fabricate a series of plasmonic Ag nanoparticles decorated GdF3:Yb3+, Er3+, Tm3+-core@porous-TiO2-shell ellipsoids, which exhibit high surface area, good stability, broadband absorption from ultraviolet to near infrared, and excellent photocatalytic activity. The results showed that photocatalytic activities of the as-obtained photocatalysts was higher than that of pure GdF3:Yb3+, Er3+, Tm3+ and GdF3:Yb3+, Er3+, Tm3+@TiO2 samples through the comparison of photodegradation rates of methyl orange under UV, visible, and NIR irradiation. The possible photocatalytic mechanism indicates that hydroxyl radicals and superoxide radical play a pivotal role in the photodegradation. Furthermore, the materials also showed exceptionally high stability and reusability under UV, visible, and NIR irradiation. All these results reveal that core–shell hierarchical ellipsoids exhibit great prospects for developing efficient solar photocatalysts.