A Novel Dual-Emission Fluorescence Probe Based on CDs and Eu3+ Functionalized UiO-66-(COOH)2 Hybrid for Visual Monitoring of Cu2

In this work, CDs@Eu-UiO-66(COOH)₂ (denoted as CDs-F2), a fluorescent material made up of carbon dots (CDs) and a Eu³⁺ functionalized metal-organic framework, has been designed and prepared via a post-synthetic modification method. The synthesized CDs-F2 presents dual emissions at 410 nm and 615 nm, which can effectively avoid environmental interference. CDs-F2 exhibits outstanding selectivity, great sensitivity, and good anti-interference for ratiometric sensing Cu²⁺ in water. The linear range is 0-200 µM and the limit of detection is 0.409 µM. Interestingly, the CDs-F2's silicon plate achieves rapid and selective detection of Cu²⁺. The change in fluorescence color can be observed by the naked eye. These results reveal that the CDs-F2 hybrid can be employed as a simple, rapid, and sensitive fluorescent probe to detect Cu²⁺. Moreover, the possible sensing mechanism of this dual-emission fluorescent probe is discussed in detail.

Design and Microwave-Assisted Synthesis of TiO2-Lanthanides Systems and Evaluation of Photocatalytic Activity under UV-LED Light Irradiation

The TiO2-Eu and TiO2-La systems were successfully synthesized using the microwave method. Based on the results of X-ray diffraction analysis, it was found that regardless of the analyzed systems, two crystal structures were noted for the obtained samples: anatase and rutile. The analysis, such as XPS and EDS, proved that the doped lanthanum and europium nano-particles are present only on the TiO2 surface without disturbing the crystal lattice. In the synthesized systems, there were no significant changes in the bandgap energy. Moreover, all the obtained systems were characterized by high thermal stability. One of the key objectives of the work, and a scientific novelty, was the introduction of UV-LED lamps into the metronidazole photo-oxidation pathway. The results of the photo-oxidation study showed that the obtained TiO2 systems doped with selected lanthanides (Eu or La) show high efficiency in the removal of metronidazole, and at the same consuming nearly 10 times less electricity compared to conventional UV lamps (high-pressure mercury lamp). Liquid-chromatography mass-spectrometry (LC-MS) analysis of an intermediate solution showed the presence of fragments of the degraded molecule by m/z 114, 83, and 60, prompting the formulation of a plausible photodegradation pathway for metronidazole.

A strategy to enhance the up-conversion luminescence of nanospherical, rod-like and tube-like NaYF4: Yb3+, Er3+ (Tm3+) by combining with carbon dots

The luminescence enhanced strategy of combining the material with carbon dots to form CDs@NaYF₄: Yb³⁺, Er³⁺ (Tm³⁺) composites is effective not only for the cubic- and hexagonal-phase materials but also for those with different morphologies.

When rare earth meets carbon nanodots: mechanisms, applications and outlook

Rare earth (RE) elements are widely used in the luminescence and magnetic fields by virtue of their abundant 4f electron configurations. However, the overall performance and aqueous stability of single-component RE materials need to be urgently improved to satisfy the requirements for multifunctional applications. Carbon nanodots (CNDs) are excellent nanocarriers with abundant functional surface groups, excellent hydrophilicity, unique photoluminescence (PL) and tunable features. Accordingly, RE-CND hybrids combine the merits of both RE and CNDs, which dramatically enhance their overall properties such as luminescent and magnetic-optical imaging performances, leading to highly promising practical applications in the future. Nevertheless, a comprehensive review focusing on the introduction and in-depth understanding of RE-CND hybrid materials has not been reported to date. This review endeavors to summarize the recent advances of RE-CNDs, including their interaction mechanisms, general synthetic strategies and applications in fluorescence, biosensing and multi-modal biomedical imaging. Finally, we present the current challenges and the possible application perspectives of newly developed RE-CND materials. We hope this review will inspire new design ideas and valuable references in this promising field in the future.

Crystallization and architecture engineering of ZnWO4 for enhanced photoluminescence

Crystal engineering of ZnWO₄ was achieved with oxalic acid and (NH₄)₂SO₄ as modifiers upon hydrothermal reaction, which produced nanorods, microplates and well-organized architectures that clearly show morphology-dependent photoluminescence.

Template-free hydrothermal synthesis of MgWO4 nanoplates and their application as photocatalysts

As a semiconductor, MgWO₄ has a potential in photocatalytic applications; however, it has been overlooked in previous studies; in this study, it has been demonstrated that MgWO₄ exhibits the ability to drive photocatalytic hydrogen evolution. Compared to nanoparticle structures, MgWO₄ nanoplates show an increased photocatalytic ability due to their higher specific surface area. Moreover, the formation mechanism of MgWO₄ nanoplates has been discussed. An oriented attachment and ripening process is proposed for the formation of the MgWO₄ nanoplates. This study demonstrates that MgWO₄ can be considered a valuable photocatalytic material, and future studies should be focused on how to promote its photocatalytic conversion efficiency.

As a semiconductor, MgWO₄ has a potential in photocatalytic applications; however, it has been overlooked in previous studies; in this study, it has been demonstrated that MgWO₄ exhibits the ability to drive photocatalytic hydrogen evolution.

Controllable synthesis of multi-morphological SrWO4:Ln3+ (Ln = Eu, Tb) hierarchical structures and their luminescence properties

Multi-morphological SrWO₄:Ln³⁺ hierarchical structures including dumbbell-like, nanosheets, rice-like, peanut-like, etc. could be controllably synthesized through readily altering reaction conditions.