Modified TiO2Structures with Enhanced Photoluminescence and Photocatalytic Activity

Photocatalytic degradation of pollutants has attracted much attention because it can effectively solve the problem of environmental pollution. SiO2@Eu(TTA)3phen@TiO2 core-shell structures were successfully synthesized for the first time by a solvothermal method involving ultrasound assistance which can optimize the rare earth complex dispersibility and achieve strong emission intensity. SiO2@Eu3+@TiO2 core-shell structures were also successfully synthesized by a similar method. Photocatalytic activity analysis showed that the photocatalytic activity factor not only depended on the rare earth ion content, but also related to the structure and size of the TiO2 nanoparticles. Photocatalytic activity increased first and then decreased with the quantity of rare earth ions. Photocatalytic activity was also superior for hollow structures compared to solid structure. Photocatalytic activity of SiO2@TiO2 particles increased with the particle size, until the size increased to 450 nm. Rare earth ions content as well as particle structures and sizes affected efficiency for the photocatalytic degradation of methyl orange. Outstanding photocatalytic activity provides the composite particles with improved potential to purify aquatic contaminants and to meet the demands of future environmental remediation applications.

Biodegradable Polylactide/Rare Earth Complexes in Light Conversion Agricultural Films

Rare earth luminescent material CaAlSiN3:Eu2+ (CEu) was applied and modified with (3-Aminopropyl) triethoxysilane (KH550) to obtain two types of rare earth conversion agents, CEu and KH550-modified CEu (KCEu). Two kinds of polylactide (PLA) conversion films were successfully prepared through solution blending. The results showed that the addition of rare earth complex increases the crystallinity of PLA. More importantly, both PLA/CEu and PLA/KCEu films showed good red-light conversion ability, which can accelerate plant growth.

Preparation and Characterization of a Novel Terbium Complex Coordinated with 10-Undecenoic Acid for UV-Cured Coatings

A UV-cured composite containing a rare earth complex was prepared for this study. First, the photoluminescent terbium complex was synthesized with a long-chain unsaturated fatty acid (10-Undecenoic acid) by a solution precipitation method, resulting in the 10-UA-Tb(III) complex. Its structure was proven by FTIR, elemental analysis, XRD, and TGA. The results indicated that the organic acid ligand successfully coordinated with the Tb3+ ion and that the complex had a chelate bidentate structure. The emission spectrum of the 10-UA-Tb(III) complex indicated that the complex can emit a bright green light with the unique luminescence of the Tb3+ ion. Furthermore, the luminescence properties of complexes with different ratios of Tb3+ and ligand were studied, and the ratio of Tb3+ and the ligand had an obvious impact on the luminescence intensity of the 10-UA-Tb(III) complex. Subsequently, the prepared rare earth complex was doped into a UV-cured coating in different proportions to obtain a UV-cured composite. The morphology of the rare earth UV-cured composite was observed by SEM. The images showed that the rare earth complex was dispersed uniformly in the polymer matrix. Moreover, the composites could emit fluorescence. Additionally, it has good thermal stability and compatibility with the resin. Therefore, these composites should have potential applications in UV curable materials, such as luminescence coatings.

Preparation of fluorescent calcium carbonate and visualization of its dispersion states in polypropylene

The dispersion states of fillers in the polymer matrix is an important factor to determine the properties of the polymer composites. Mastering the dispersion structure of inorganic minerals such as calcium carbonate in the polymer matrix is of great significance for the design of high performant polymer composites. Currently, due to the limitations of conventional electron microscope imaging capabilities, it is difficult to understand the internal dispersion structure of fillers in polymer composites comprehensively, regionally and stereoscopically. Here, we successfully embed the rare earth complex into the silica of the calcium carbonate surface to realize the fluorescent labeling of the calcium carbonate fillers. The fluorescent calcium carbonate exhibited broad excitation band ranging from 220 nm to 440 nm and showed bright red under ultraviolet light (365 nm). The two-dimensional dispersion states of the fillers at different depths in the polymer composite were obtained by the fluorescent imaging ability of laser scanning confocal microscope; these two-dimensional confocal images were further three-dimensionally reconstructed through Avizo Fire VSG software, and the spatial distribution of fillers in polymer composite was obtained without damage. This characterization method provides a new noninvasive method for studying the dispersion structure of fillers in polymers.