One-Step Hydrothermal Synthesis of Highly Fluorescent MoS2 Quantum Dots for Lead Ion Detection in Aqueous Solutions.

Lead ions in water are harmful to human health and ecosystems because of their high toxicity and nondegradability. It is important to explore effective fluorescence probes for Pb2+ detection. In this work, surface-functionalized molybdenum disulfide quantum dots (MoS2 QDs) were prepared using a hydrothermal method, and ammonium tetrathiomolybdate and glutathione were used as precursors. The photoluminescence quantum yield of MoS2 QDs can be improved to 20.4%, which is higher than that for MoS2 QDs reported in current research. The as-prepared MoS2 QDs demonstrate high selectivity and sensitivity for Pb2+ ions, and the limit of detection is 0.056 µM. The photoluminescence decay dynamics for MoS2 QDs in the presence of Pb2+ ions in different concentrations indicate that the fluorescence quenching originated from nonradiative electron transfer from excited MoS2 QDs to the Pb2+ ion. The prepared MoS2 QDs have great prospect and are expected to become a good method for lead ion detection.

The Lattice Distortion, Defect Evolution and Electrochemical Performance Improvement in Zn-VO2(B) Nanorods.

Cathode materials of energy storage batteries have attracted extensive attention because of the importance in deciding the rate performance and long cycle property of batteries. Herein, we report a simple and environmentally friendly solvothermal method to prepare Zn-doped VO2(B) cathode materials. The introduction of zinc ions can effectively regulate the lattice structure, surface morphology and internal defect state of Zn-VO2(B) nano materials. The sample with Zn content x = 1.5% has smaller cell volume and grain size, and higher concentration of vacancy defects. These microstructures ensure the structural stability during ion embedding process and, thus, this sample shows excellent electrochemical performances. The capacitance retention rate still maintains 88% after 1000 cycles at the current density of 0.1 A·g-1. The enhanced performances of Zn-doped VO2(B) samples may lay a foundation for the improvement of electrochemical performances of VO2(B) cathode materials for energy storage batteries in the future.

A New Family of Disorder-Free Rare-Earth-Based Kagome Lattice Magnets: Structure and Magnetic Characterizations of RE3BWO9 (RE = Pr, Nd, Gd-Ho) Boratotungstates.

Exploration of rare-earth (RE)-based Kagomé lattice magnets with spin-orbital entangled jeff = 1/2 moments will provide a new platform for investigating the exotic magnetic phases. Here, we report a new family of RE3BWO9 (RE = Pr,Nd,Gd-Ho) boratotungstates with magnetic RE3+ ions arranged on Kagomé lattice and perform its structure and magnetic characterizations. These serial compounds crystallize in a hexagonal coordinated structure with space group P63 (no. 173), where magnetic RE3+ ions have distorted Kagomé lattice connections within the ab plane and stacked in an AB-type fashion along the c axis. The interlayer RE-RE separation is comparable with that of the intralayer distance, forming 3-dimensional (3D) exchange coupled magnetic framework of RE3+ ions. The magnetic susceptibility data of RE3BWO9 (RE = Pr, Nd, Gd-Ho) reveal dominant antiferromagnetic interactions between magnetic RE3+ ions, but without visible magnetic ordering down to 2 K. The magnetization analyses for different RE3+ ions show diverse anisotropic behaviors, making RE3BWO9 as an appealing Kagomé-lattice antiferromagnet to explore exotic magnetic phases.