Synthesis, characterization, and visible photocatalytic performance of Zn₂GeO₄ nanobelts modified by CdS quantum dots

Zn₂GeO₄ nanobelts modified by CdS quantum dots (Zn₂GeO₄/CdS) were prepared successfully by chemical bath deposition. The novel photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis diffuse reflectance spectroscopy. It was found that Zn₂GeO₄/CdS consisted of uniform rhombohedral phase Zn₂GeO₄ nanobelts with highly dispersed cubic phase CdS quantum dots, and the Zn₂GeO₄/CdS exhibited strong visible light absorption at about 510nm. The photocatalytic activities of the catalysts were evaluated by the discoloration of Rhodamine B under visible light illumination and were compared with that of pure Zn₂GeO₄ nanobelts. The results suggested that the composite photocatalyst had much higher photocatalytic activities than pure Zn₂GeO₄ nanobelts under irradiation of visible light. Meanwhile, no obvious deactivation of Zn₂GeO₄/CdS was observed after the three recycles experiments in photodegradation of RhB. The possible mechanism of visible light photocatalytic degradation is also proposed.