Mesoporous ZnO@Co3O4 Nanosphere for Sensitive Detection of 3-Hydroxy-2-Butanone

The mixed semiconductor metal oxides as the gas sensor can enhance the sensitivity compared with the metal oxide respectively. In this study, the mesoporous ZnO@Co3O4 nanosphere was prepared through the simple hydrothermal synthesis method of ZIF-L-Zn@Co, the cage construction of mesoporous ZnO@Co3O4 nanosphere was remained unchanged after the calcination of the ZIF-L-Zn@Co at 600℃ for 2 h in the air. The mesoporous ZnO@Co3O4 nanosphere was selected as the gas sensor for the detection of 3-Hydroxy-2-Butanone. Compared with the ZnO and Co3O4 respectively, the mesoporous ZnO@Co3O4 nanosphere as the gas sensor shows the high sensitivity, selectivity and stability.

Efficient One-pot Synthesis of 4 Hydroxy-2H Chromene by heterogeneously catalyzed ZnO NP and mesoporous aluminosilicate catalysts in solvent free condition.

4Hydroxy-2H Chromenes are fused benzopyran rings, an important class of biologically active compounds, widely used as antibacterial, antiviral, antitumor, and anticancer agents. In this present paper, we report the 4 Hydroxy-2H Chromenes synthesis by using two catalysts namely, (i) ZnO nanoparticles and (ii) mesoporous ZnO/AlSBA-15 (7) catalysts. The ZnO NP catalyst was prepared by using leaf extract while ZnO/AlSBA-15(7) catalysts were prepared by the wet chemical route. All catalysts were characterized by XRD, SEM, EDS, FTIR, and N2 sorption techniques. The catalytic activity of the synthesized catalyst was evaluated in the one-pot reaction using aromatic aldehyde and Coumarin, and found to be maximum yield of 81% at temperature 80°C, a catalyst dose of 10 mmol %, in time limit of 4h.

Ethanol Sensing Properties and First Principles Study of Au Supported on Mesoporous ZnO Derived from Metal Organic Framework ZIF-8

It is of great significance to develop ethanol sensors with high sensitivity and low detection temperature. Hence, we prepared Au-supported material on mesoporous ZnO composites derived from a metal-organic framework ZIF-8 for the detection of ethanol gas. The obtained Au/ZnO materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM) and nitrogen adsorption and desorption isotherms. The results showed that the Au/ZnO-1.0 sample maintains a three-dimensional (3D) dodecahedron structure with a larger specific surface area (22.79 m2 g−1) and has more oxygen vacancies. Because of the unique ZIF structure, abundant surface defects and the formation of Au-ZnO Schottky junctions, an Au/ZnO-1.0 sensor has a response factor of 37.74 for 100 ppm ethanol at 250 °C, which is about 6 times that of pure ZnO material. In addition, the Au/ZnO-1.0 sensor has good selectivity for ethanol. According to density functional theory (DFT) calculations, the adsorption energy of Au/ZnO for ethanol (−1.813 eV) is significantly greater than that of pure ZnO (−0.217 eV). Furthermore, the adsorption energy for ethanol is greater than that of other gases.