MoS ₂ nanosheets with higher adsorption capacity for dyes.

Various kinds of copper sulfides (CuS, a mixture of Cu₇S₄–CuS and Cu₉S₅) were synthesized by simply adjusting the amount of copper chloride and sodium sulfide in a solvothermal process. The different molar ratios of copper chloride and sodium sulfide result in the formation of different kinds of copper sulfides with various morphologies, such as tiny particle, hexagonal plate and octahedron. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. And the optical properties of the products were recorded by means of UV-Vis absorption and photoluminescence spectroscopy. Moreover, due to the presence of visible light, we found that the catalytic activities of the products for oxidation and decomposition of Rhodamine B with the assistance of hydrogen peroxide were enhanced, and the degradation efficiency of RhB was increased from 40% to 98% in 15 minutes at room temperature.

The engineering of an efficient electrochemical sensor based on a bismuth sulfide/reduced graphene oxide (Bi₂S₃/rGO) composite to detect ascorbic acid (AA) is reported. The Bi₂S₃ nanorods/rGO composite was synthesized using a facile hydrothermal method. By varying the amount of graphene oxide (GO) added to the synthesis, the morphology and size of Bi₂S₃ nanorods anchored on the surface of rGO can be tuned. Compared to a bare glassy carbon electrode (GCE), the GCE modified with Bi₂S₃/rGO composite presented enhanced electrochemical performance, which was attributed to the optimal electron transport between the rGO support and the loaded Bi₂S₃ as well as to an increase in the number of active catalytic sites. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis of Bi₂S₃/rGO/GCE demonstrate that the active Bi₂S₃/rGO layer on GCE plays an important role in the electrochemical behavior of the sensor. In particular, the Bi₂S₃/rGO/GCE sensor shows a wide detecting range (5.0–1200 μM), low detection limit (2.9 µM), good sensitivity (268.8 μA mM⁻¹ cm⁻²), and sufficient recovery values (97.1–101.6%) for the detection of ascorbic acid.

Tunable ZnS–CuS microspheres were readily prepared via replacing the Zn²⁺ ions of solid ZnS microspheres with Cu²⁺ ions in an aqueous solution under a hydrothermal condition, and were then characterized by XRD, SEM, TEM, UV-Vis, PL and XPS techniques. The thickness of CuS shell on the surface of ZnS core can be controlled by changing the ion-exchange time, which plays an important role in the visible light photodegradation efficiency of rhodamine B in aqueous solution. Degradation rate can rapidly reach ca. 72% under visible light irradiation for 15 min and then ca. 98% after 60 min using the ZnS–CuS microspheres as the photocatalyst.