ZnIn 2 S 4 nanosheets with hexagonal and cubic structures have been prepared through a liquid ultrasonic exfoliation method and another strategy involving a lamellar hybrid, respectively. The structure, morphology, and composition properties of the as-prepared samples were characterized using X-ray powder diffraction, UV-vis spectrophotometry, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The photocatalytic activities of the as-prepared ZnIn 2 S 4 samples were evaluated by methyl formate formation from CO 2 photoreduction in methanol as a solution of absorbing CO 2 and reducing agent, and the activity over hexagonal ZnIn 2 S 4 was better than over cubic ZnIn 2 S 4 . In addition, both hexagonal and cubic ZnIn 2 S 4 nanosheets displayed much higher reactivity than ZnIn 2 S 4 microspheres prepared by the hydrothermal method. The electronic structures of the two phases of ZnIn 2 S 4 were investigated in the light of density functional theory.

Different shape of bismuth sulfide (Bi2S3), including nanoparticles, and urchin-like, microspheres hierarchical nanostructures, have been successfully fabricated using a facile and template-free solvothermal method. Their crystal and porous structures, morphologies, as well as the optical absorption were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS) and nitrogen sorption. The electron microscopy observations showed that both the sulfur sources and solvents greatly affected the morphologies of the as-prepared Bi2S3. Compared with Bi2S3 nanoparticles, the hierarchical architectures exhibited higher activity for photocatalytic reduction of CO2 to methyl formate (MF) in methanol, and Bi2S3 microspheres showed the highest activity. This was attributed to their special hierarchical structure, good permeability and high light-harvesting capacity.

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We present the design of a new type of irregular metamaterial structure that can achieve ultra-wideband absorption. The structure is created using 3D-printing to create a shell and contains multiple layers of water. The structure can achieve absorption levels greater than 0.9 in the 6.8–21.0 GHz range, with a relative bandwidth of 101.93%. The absorber also works in a wide range of incidence angles with different modes and is polarization insensitive. Measurement results obtained from a microwave experiment coincide well with the simulation results. The proposed metamaterial could be broadly applied in various civilian and military products in the future.