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A zirconia-based catalyst with controlled crystalline phases is synthesized through a simple thermal decomposition of a parent UiO-66 single precursor. The introduction of Ti(IV) and Hf(IV) cation into the Zr(IV) framework has been successfully obtained to tune the photocatalytic activity over methyl orange (MO) solution. Their resulting crystalline phases, morphologies, elemental analysis, band gap values, surface area, and photocatalytic degradation study over MO dye are presented and discussed. The tetragonal zirconia (t-ZrO2) catalyst exhibits the highest photocatalytic activity with 89% decoloration efficiency under UV irradiation (λ = 254 nm) for 300 min compared to m-ZrO2 (67%), the mixed phases (t-ZrO2 and m-ZrO2), as well as the synthesized mixed oxides ZrO2-MO2 (M = Ti or Hf), where the photocatalytic activities are 74% and 63%, respectively. This result is on par with commercially available anatase TiO2 and other reported t-ZrO2 catalysts. [ABSTRACT FROM AUTHOR]

Dyes used in textile industry contained organic compounds that cause water pollution. Photodegradation is a common method applied for dyes treatment in wastewater. Metal oxides had been widely used as photocatalyst for organic pollutant degradation in water. However, metal oxides exhibit wide band gap and fast charge (hole and electron) recombination time which decrease the photocatalytic activity. Metal-Organic Frameworks (MOFs) has been developed as an alternative photocatalyst that could decrease the recombination time and lower the band gap. Copper and zirconium-based MOFs with 1,4-benzenedicarboxylic (BDC) linker known as CuBDC and UiO-66, respectively, were used as photocatalyst for the degradation of methyl orange (MO). The photocatalytic activity of CuBDC and UiO-66 was investigated by determining the degradation rate of MO under visible and UV light. CuBDC and UiO-66 were successfully synthesized by solvothermal method and characterized by Powder X-Ray Diffraction (PXRD) to identify the phase and UV-Vis Diffuse Reflectance Spectra (UV-vis DRS) to determine the band gap. The degradation percentage of MO with CuBDC under visible and UV light were 3.6 and 3.3 %, respectively, while the degradation percentage of MO with UiO-66 under visible and UV light were 6.6 % and 36.4 % in 40 min reaction. UiO-66 exhibited a better photocatalytic activity than CuBDC for the degradation of MO under visible and UV light. [ABSTRACT FROM AUTHOR]

Metals with high hardness and corrosion resistance are widely used in many industrial applications. The hardness and corrosion resistance can be enhanced by combining the metal with other metals forming alloys. In this study Ni was combined with W to form Ni-W alloy using the electrodeposition method and tributylmethylammonium methyl sulfate (MTBS) is used as an additive to improve the hardness and the corrosion resistance. The hardness and corrosion resistance of Ni-W alloy synthesized using the electrodeposition method without and in the presence of MTBS are examined. The formation of Ni-W alloy was determined by X-Ray Diffraction (XRD), Ni-W alloy's hardness - by microhardness-Vickers and their corrosion resistance using Electrochemical Impedance Spectroscopy (EIS). The crystallite size of synthesized Ni-W alloy without and in the presence of MTBS before heat treatment is 4.7 nm and 3.5 nm, and after heat treatment is 20.4 nm and 24.7 nm, respectively. The hardness of synthesized Ni-W alloy without and in the presence of MTBS before heat treatment is 678 ± 48 HV and 871 ± 105 HV, and after heat treatment it is 1081 ± 41 HV and 1456 ± 136 HV, respectively. EIS measurement results show that Ni-W alloy without MTBS has a bit higher corrosion resistance (Rct = 763 Ω cm²) than Ni-W alloy with MTBS (Rct = 688 Ω cm²). [ABSTRACT FROM AUTHOR]

Abstract: The influence of multiple additions of two oxides, Cr2O3 and Nb2O5, as additives on the hydrogen sorption kinetics of MgH2 after milling was investigated. We found that the desorption kinetics of MgH2 were improved more by multiple oxide addition than by single addition. Even for the milled MgH2 micrometric size powders, the high hydrogen capacity with fast kinetics were achieved for the powders after addition of 0.2mol% Cr2O3 +1mol% Nb2O5. For this composition, the hydride desorbed about 5wt.% hydrogen within 20min and absorbed about 6wt.% in 5min at 300°C. Furthermore, the desorption temperature was decreased by 100°C, compared to MgH2 without any oxide addition, and the activation energy for the hydrogen desorption was estimated to be about 185kJmol−1, while that for MgH2 without oxide was about 206kJmol−1. [Copyright &y& Elsevier]

This SO4/TiO2 catalyst as a heterogeneous acidic catalyst was synthesized in various concentrations of H2SO4. The activity and selectivity of the SO4/TiO2 catalyst on the dehydration reaction of ethanol to diethyl ether were studied as well. The SO4/TiO2 was prepared from TiO2 powder by wet impregnation method with a various aqueous solution of H2SO4 (1; 2; 3 M H2SO4) and calcination temperature (400, 500, and 600 °C) to obtain a catalyst with optimum acidity. The catalysts were characterized using FTIR, XRD, SEM-EDX, SAA, TGA/DSC, and acidity test gravimetrically with ammonia. The liquid product of DEE was analyzed by gas chromatography (GC) to analyze the selectivity of the catalyst. The catalyst TS-3-400 had the highest activity and selectivity in the dehydration reaction of ethanol to diethyl ether at a temperature of 225 °C, with a conversion of 51.83% and a DEE selectivity of 1.72%. [ABSTRACT FROM AUTHOR]