In this study UiO-66 and UiO-66-NH 2 were synthesized by solvothermal method. The effect of preparation conditions on the quality of UiO-66-NH 2 was studied. The obtained material has been characterized by x-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimatric analysis (TGA), scanning electron microscopy (SEM) and nitrogen physisorption measurements (BET). The CO 2 and CH 4 physisorption measurements were carried out using a high pressure volumetric analyzer (Micromeritics HPVA-100). The results showed that the UiO-66-NH 2 of ball shape crystalline had been obtained and characterized by high surface area (BET) up to 876 m 2 g −1 , specific volume 0.379 cm 3 g −1 , pore radius 9.5 Å and thermal stability up to 673 K, respectively. The experiments indicated that in comparison with UiO-66 the addition of NH 2 is able to increase the CO 2 and CH 4 storage capacity at 1 bar and 303 K twice from 28.43 cm 3 g −1 up to 52 cm 3 g −1 and from 6.68 cm 3 g −1 to 11.1 cm 3 g −1 , respectively.
By dip-coating technique the thin films of nano-photocatalysts TiO2, Cr-doped TiO2, LaBO3 perovskites (B = Fe, Mn, and Co) prepared by sol-gel method, and UiO66-NH2 prepared by a solvothermal were obtained and employed for gas phase degradation of p-xylene. Physicochemical characteristics of the catalysts were examined by the methods of BET, SEM, TEM, XRD, FT-IR, TGA, Raman and UV–vis spectroscopies. The thickness of film was determined by a Veeco-American Dektek 6M instrument. The activity of catalysts was evaluated in deep photooxidation of p-xylene in a microflow reactor at room temperature with the radiation sources of a UV (λ = 365 nm) and LED lamps (λ = 400–510 nm). The obtained results showed that TiO2 and TiO2 doped Cr thin films was featured by an anatase phase with nanoparticles of 10–100 nm. Doping TiO2 with 0.1%mol Cr2O3 led to reduce band gap energy from 3.01 down to 1.99 eV and extend the spectrum of photon absorption to the visible region (λ = 622 nm). LaBO3 perovkite thin films were also featured by a crystal phase with average particle nanosize of 8–40 nm, a BET surface area of 17.6–32.7 m2 g−1 and band gap energy of 1.87–2.20 eV. UiO66-NH2 was obtained in the ball shape of 100–200 nm, a BET surface area of 576 m2 g−1 and a band gap energy of 2.83 eV. The low band gap energy nano-photocatalysts based on Cr-doped TiO2 and LaBO3 perovskites exhibited highly stable and active for photo-degradation of p-xylene in the gas phase under radiation of UV–vis light. Perovskite LaFeO3 and Cr–TiO2 thin films were the best photocatalysts with a decomposition yield being reached up to 1.70 gp-xylene/gcat.
In this study a metal-organic framework (MOF-199) has been synthesized by solvent-thermal method. The conditions of preparation and activation processes have been investigated. The obtained material was characterized by methods of x-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimatric analysis (TGA) and scanning electron microscopy (SEM). The CO2 adsorption measurements were carried out on a high pressure volumetric analyzer (Micromeritics HPVA − 100). According to experimental results, Cu(NO3)2·3H2O has been shown to be the best copper(II) precursor for the synthesis of MOF-199 and N,N-dimethylformamide (DMF):C2H5OH:H2O with the ratio of 1:1:1 has been chosen as the most suitable solvent. The appropriate activation condition has been determined as follows: activate at 200 °C for 5 h and use CH3OH as the solvent to remove DMF. At the optimal conditions, an octahedral shape and three-dimensional (3D) structure of crystallite of MOF-199 was obtained. The synthesized MOF-199 expressed a high value of specific surface area (1448 m2 g−1 by Brunauer–Emmet–Teller (BET) method and 2028 m2 g−1 by Langmuir method) with Ta porous size of crystal of 11.8 Å and specific volume of 0.693 cm3 g−1; it was still stable up to 332 °C and its CO2 storage capacity reached to 206.59 cm3 (STP) g−1 at 25.76 bar.
Enhancement of water-gas shift reaction efficiency: catalysts and the catalyst bed arrangement Natal'ya A Baronskaya, Tat'yana P Minyukova, Aleksandr A Khassin et al. In this study four optimal catalysts on the basis of Pt-CuO supported on γ-Al 2 O 3 , TiO 2 , CeO 2 and γ-Al 2 O 3 + CeO 2 have been prepared and studied. Characterizations of the catalysts have been carried out by methods of N 2 adsorption, x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and temperatureprogrammed-reduction (TPR). The activity of these catalysts for deep oxidation of CO, p-xylene and their mixture was assessed at temperature range 75−300°C. The results showed that the presence of CO in a mixture with p-xylene has a beneficial effect on the rate of p-xylene conversion; meanwhile the presence of p-xylene shows the inhibition on CO oxidation. In the reactions of the mixture, oxidation of CO and p-xylene occurred simultaneously on PtCuO catalyst supported on γ-Al 2 O 3 , TiO 2 , CeO 2 carriers, but on catalyst PtCu/CeAl the oxidation of p-xylene can proceed only when CO is consumed entirely. Addition of 1.1 to 3.2% mol steam into the gas mixture exhibits no effect on the conversion of CO; meanwhile, it shows the limited effect on oxidation rate of p-xylene on hydrophobic catalysts (PtCu/Ce, PtCu/CeAl and PtCu/ Ti), but strong inhibition on hydrophilic catalyst (PtCu/Al). However, this negative effect of water was reversible.
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