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.

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.

Low photoluminescence (PL) quantum yield of molybdenum disulfide (MoS₂) quantum dots (QDs) has limited practical application as potential fluorescent materials. Here, we report the intercalation of aluminum ion (Al³⁺) to enhance the PL of MoS₂ QDs and the underlying mechanism. With detailed characterization and exciton dynamics study, we suggest that additional surface states including new emission centers have been effectively introduced to MoS₂ QDs by the Al³⁺ intercalation. The synergy of new radiative pathway for exciton recombination and the passivation of non-radiative surface traps is responsible for the enhanced fluorescence of MoS₂ QDs. Our findings demonstrate an efficient strategy to improve the optical properties of MoS₂ QDs and are important for understanding the regulation effect of surface states on the emission of two dimensional sulfide QDs.