近红外光驱动的UCNPs/ZnxCd1-xS纳米复合结构的化学合成并用于光化学还原六价铬
摘要
Abstract Photocatalysis driven by near-infrared (NIR) light is of scientific and technological interest for exploiting solar energy. In this study, we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles (UCNPs) and alloyed ZnxCd1-xS, which can be excited using NIR or visible light. Morphologies, phase, and chemical composition have been investigated using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and atomic absorption spectroscopy. Moreover, we found that amorphous TiO2 layers existing in the final samples play an important role in formation of UCNPs@ZnxCd1-xS yolk-shell nanoparticles, which bind the as-prepared ZnxCd1-xS nanoparticles tightly to form yolk-shell nanoparticles. The chemical composition of alloyed ZnxCd1-xS can be tunable by adjusting the amount of the Cd and Zn source compounds. The photochemical reduction of Cr(VI) in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light, showing efficient photoreduction and Cr(VI) removal over the as-prepared UCNPs@ZnxCd1-xS/TiO2 yolk-shell nanoparticles. The as-prepared UCNPs@ZnxCd1-xS/TiO2 nanoparticles show excellent production of hydroxyl radicals, which are responsible for the photochemical reduction of Cr(VI) to Cr(III). This study will provide an alternative strategy for environmental wastewater treatment, making full use of solar energy.