Shape-Controlled Synthesis of ZnS Nanostructures: A Simple and Rapid Method for One-Dimensional Materials by Plasma

In this paper, ZnS one-dimensional (1D) nanostructures including tetrapods, nanorods, nanobelts, and nanoslices were selectively synthesized by using RF thermal plasma in a wall-free way. The feeding rate and the cooling flow rate were the critical experimental parameters for defining the morphology of the final products. The detailed structures of synthesized ZnS nanostructures were studied through transmission electron microscope, X-ray diffraction, and high-resolution transmission electron microscope. A collision-controlled growth mechanism was proposed to explain the growth process that occurred exclusively in the gas current by a flowing way, and the whole process was completed in several seconds. In conclusion, the present synthetic route provides a facile way to synthesize ZnS and other hexagonal-structured 1D nanostructures in a rapid and scalable way

Effect of acidic surface functional groups on Cr(VI) removal by activated carbon from aqueous solution

The activated carbon with high surface area was prepared by KOH activation. It was further modified by H2SO4 and HNO3 to introduce more surface functional groups. The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms. The morphology of those activated carbons was characterized using scanning electronic microscopy (SEM). The surface functional groups were determined by Fourier transform infrared spectroscopy (FTIR). The quantity of those groups was measured by the Boehm titration method. Cr(VI) removal by the activated carbons from aqueous solution was investigated at different pH values. The results show that compared with H2SO4, HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon. The pH value of the solution plays a key role in the Cr(VI) removal. The ability of reducing Cr(VI) to Cr(III) by the activated carbons is relative to the acidic surface functional groups. At higher pH values, the Cr(VI) removal ratio is improved by increasing the acidic surface functional groups of the activated carbons. At lower pH values, however, the acidic surface functional groups almost have no effect on the Cr(VI) removal by the activated carbon from aqueous solution

Effect of acidic surface functional groups on Cr(VI) removal by activated carbon from aqueous solution

The activated carbon with high surface area was prepared by KOH activation. It was further modified by H(2)SO(4) and HNO(3) to introduce more surface functional groups. The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms. The morphology of those activated carbons was characterized using scanning electronic microscopy (SEM). The surface functional groups were determined by Fourier transform infrared spectroscopy (FTIR). The quantity of those groups was measured by the Boehm titration method. Cr(VI) removal by the activated carbons from aqueous solution was investigated at different pH values. The results show that compared with H(2)SO(4), HNO(3) destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon. The pH value of the solution plays a key role in the Cr(VI) removal. The ability of reducing Cr(VI) to Cr(III) by the activated carbons is relative to the acidic surface functional groups. At higher pH values, the Cr(VI) removal ratio is improved by increasing the acidic surface functional groups of the activated carbons. At lower pH values, however, the acidic surface functional groups almost have no effect on the Cr(VI) removal by the activated carbon from aqueous solution

Winged Fruits of Deviacer in the Oligocene from the Ningming Basin in Guangxi, South China.

Deviacer guangxiensis Chen & Manchester sp. nov. is described based on asymmetric samaras from the Oligocene Ningming Formation in Guangxi, South China, representing the first documentation of Deviacer fossils in Asia. The Oligocene species, with relatively large fruits, represents the youngest record of the genus so far known; all other records are from the Paleocene and Eocene, or late Eocene-early Oligocene in western North America and Europe. It indicates that the extinct genus, Deviacer, was widely distributed in the northern hemisphere during the Paleogene

Promotion of transition metal oxides on the NH3-SCR performance of ZrO2-CeO2 catalyst

Chromium oxide and manganese oxide promoted ZrO2-CeO2 catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NOx with NH3. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Brunauer-Emmett-Teller (BET) surface area analysis, H-2 temperature-programmed reduction (H-2-TPR), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH3-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO2-CeO2 binary oxide for the low temperature NH3-SCR, mainly because of the high specific surface area, more surface oxygen species, improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO2 and H2O. Cr-Zr-Ce mixed oxide exhibited&gt; 80% NOx conversion at a wide temperature window of 100 degrees C-300 degrees C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr6+. The present mixed oxide can be a candidate for the low temperature abatement of NOx. (C) Higher Education Press and Springer-Verlag Berlin Heidelberg 2017</p

RSC Adv.

We demonstrate the first example of efficient and cost-effective graphene on silicon solar cells prepared using spray coating. The spray coating process is optimized by investigating the effects of substrate temperature and graphene film thickness on device performance. With the aid of a simple hydroquinone/methanol surface passivation method, spray-coated G/Si solar cells with a power conversion efficiency of 4.41% can be obtained. Our method is faster and simpler than conventional fabrication methods, and is easy to scale up, highlighting its great potential in the mass production of efficient and low-cost G/Si solar cells.We demonstrate the first example of efficient and cost-effective graphene on silicon solar cells prepared using spray coating. The spray coating process is optimized by investigating the effects of substrate temperature and graphene film thickness on device performance. With the aid of a simple hydroquinone/methanol surface passivation method, spray-coated G/Si solar cells with a power conversion efficiency of 4.41% can be obtained. Our method is faster and simpler than conventional fabrication methods, and is easy to scale up, highlighting its great potential in the mass production of efficient and low-cost G/Si solar cells

Promotion of transition metal oxides on the NH_3-SCR performance of ZrO_2-CeO_2 catalyst

Chromium oxide and manganese oxide promoted ZrO_2-CeO_2 catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NO_x with NH_3. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM),Brunauer-Emmett-Teller (BET) surface area analysis,H_2 temperature-programmed reduction (H_2-TPR),and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH_3-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO_2-CeO_2 binary oxide for the low temperature NH_3-SCR, mainly because of the high specific surface area, more surface oxygen species,improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO_2 and H_2O. Cr-Zr-Ce mixed oxide exhibited >80% NO_x conversion at a wide temperature window of 100°C-300°C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr~(6+). The present mixed oxide can be a candidate for the low temperature abatement of NO_x

Synthesis of Hierarchical Hollow MnO2 Microspheres and Potential Application in Abatement of VOCs

Hierarchical hollow MnO2 microspheres have been synthesized by a facile hydrothermal method based on the decomposition of KMnO4 precursor in nitric acid solution in the presence of Ce3+ ions. The hierarchical hollow microspheres consisted of discuslike nanoplatelets and nanorods. The BrunauerEmmetTeller (BET) specific surface area and the pore volume of the hierarchical hollow microspheres are 29.2 m(2) g(1) and 0.30 cm(3) g(1), respectively. A possible formation mechanism of hierarchical hollow microspheres is proposed. Ce3+ ions play a crucial role in controlling the morphology and crystalline structure of MnO2. The concentration of Ce3+ ions is a key factor for the formation of the hierarchical hollow microspheres. The as-prepared hierarchical hollow MnO2 microspheres exhibit high catalytic ability for the oxidation of benzene