II-VI Semiconductor-Based Conductometric Gas Sensors: Is There a Future for These Sensors?

A review of the state of research in the development of conductometric gas sensors based on II-VI semiconductors is given. It was shown that II-VI compounds indeed have properties that are necessary for the development of highly efficient gas sensors. In this case, to achieve the required parameters, all approaches developed for metal oxides can be used. At the same time, during a detailed review, it was concluded that sensors based on II-VI compounds have no prospects for appearing on the gas sensor market. The main obstacle is the instability of the surface state, which leads to poor reproducibility of parameters and drift of sensor characteristics during operation.

Multishelled Transition Metal-Based Microspheres: Synthesis and Applications for Batteries and Supercapacitors

With the rapid growth of material innovations, multishelled hollow nanostructures are of tremendous interest due to their unique structural features and attractive physicochemical properties. Continued effort has been made in the geometric manipulation, composition complexity, and construction diversity of this material, expanding its applications. Energy storage technology has benefited from the large surface area, short transport path, and excellent buffering ability of the nanostructures. In this work, the general synthesis of multishelled hollow structures, especially with architecture versatility, is summarized. A wealth of attractive properties is also discussed for a wide area of potential applications based on energy storage systems, including Li-ion/Na-ion batteries, supercapacitors, and Li-S batteries. Finally, the emerging challenges and outlook for multishelled hollow structures are mentioned.

Molybdenum-doped ZnS sheets with dominant {111} facets for enhanced visible light photocatalytic activities

ZnS is widely used as a semiconductor photocatalyst in photo-electrochemical water splitting and photodegradation under ultraviolet (UV)-light irradiation. In this work, Molybdenum (Mo)-doped ZnS sheets with dominant {111} facets are developed using a hydrothermal method with Mo ions as precursors to realize non-visible-light photocatalytic activity and reduce the recombination rate of photoexcited carriers in ZnS. Mo ions are found to play a key role in the growth process of the sheet-like structure. Mo-dopants in the ZnS sheets introduce the acceptor energy levels among the bandgaps. The light absorption range of Mo-doped ZnS sheets covers the entire visible light and even extends to the near-infrared light region. The p-type Mo-doped ZnS sheets exhibit enhanced photocatalytic activities under visible light irradiation, which is promising for the photo-electrochemistry and photo-oxidation applications.

Synthesis, Characterisation, and Photocatalytic Behaviour of Mesoporous ZnS Nanoparticles Prepared Using By-Product Templating

High surface area mesoporous ZnS nanoparticles (MZN) were obtained with the aid of the by-product of the synthesising reaction. This by-product, namely NaNO3, can be considered as a soft template responsible for the formation of pores. Ethanol and water were chosen as the synthesis media. Ultrasonic waves were used as an accelerator for the synthesis of MZNs. Photocatalytic activities of the synthesised samples for the degradation of methylene blue (MB) were investigated under ultraviolet irradiation. Synthesised specimens were characterised using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, diffuse reflectance spectroscopy, N2-physisorption, and FT-IR spectroscopy. Results indicated that the synthesis media has a pronounced effect on the surface properties of the final porous particles by several mechanisms. The specific surface area of the MZN samples synthesised in water and ethanol were determined to be 53 and 201 m2 g−1, respectively. The difference in the specific surface area was attributed to the weak solvation of S2− ions (Na2S·5H2O in ethanol) and also to the by-product of the synthesis reaction. The photocatalytic behaviour of the mesoporous ZnS nanoparticles synthesised in these two media were investigated and the results have been interpreted with the aid of effective surface area, pore volume, and bandgap energy of the specimens.

Self-assembled ZnS nanospheres with nanoscale porosity as an efficient carrier for the delivery of doxorubicin

Self-aggregated mesoporous ZnS nanomaterials have been utilized as a drug-delivery vehicle that can activates the apoptotic pathway with a minimal concentration of doxorubicin and it can regulates lymphocytic leukemia cell growth.

Immobilization of cadmium ions to synthesis hierarchical flowerlike cadmium phosphates microspheres and their application in the degradation of organic pollutants under light irradiation

Hierarchical flowerlike Cd₅H₂(PO₄)₄·4H₂O and Cd₅(PO₄)₂P₂O₇ microspheres were prepared by cadmium ion immobilization followed by an annealing treatment. Cd₅(PO₄)₂P₂O₇ was applied as a novel photocatalyst toward dye degradation under light irradiation.

Tunable blue-green-emitting wurtzite ZnS:Mg nanosheet-assembled hierarchical spheres for near-UV white LEDs

Mg-doped ZnS hierarchical spheres have been synthesized via hydrothermal method using mixed solvents of ethylenediamine and DI water without any surface-active agent. The surface morphology and microstructure studies revealed that the hierarchical spheres were consisted of many well-aligned nanosheets with width 10 nm and length about 50 ~ 100 nm. X-Ray diffraction results show that the ZnS:Mg hierarchical spheres have wurtzite structure with high crystallinity. The absorption edge in the diffuse reflection spectra shifts towards lower wavelength with increasing Mg concentration, indicating an expansion in the bandgap energy that is estimated to be in the range of 3.28 to 3.47 eV. Blue-green photoluminescence with tunable intensity and peak position was observed depending on the Mg content. The Mg2+-activated ZnS phosphor can be good candidates for blue-green components in near-UV white light-emitting diodes.